Camber Variability in Prestressed Concrete Bridge Beams
|
|
- Gillian Blake
- 6 years ago
- Views:
Transcription
1 CONCRETE BRIDGE TECHNOLOGY Camber Variability in Prestressed Conrete Bridge Beams by Dr. Maher Tadros, econstrut Beams ast with extra amber in storage yard at Conrete Tehnology Corporation; amber shown is exeptionally large for illustration purposes. Photo: Conrete Tehnology Corporation. Preast, prestressed onrete girders experiene amber (upward defletion) when the prestressing strands are detensioned and the prestressing fore is transferred from the asting bed to the onrete member. When the girder is stored in the yard of the preast manufaturer, its amber ontinues to hange with time, influened by the ambient air onditions, and even the orientation of the girder as it is exposed to the sun. When the girder is ereted on its seats at the bridge site and just before the dek is plaed, its amber at that time affets the haunh (build up) onrete required to ensure that the top of dek surfae meets the roadway profile requirements. a Strand group debond length plus half transfer length b L Profile of a group of strands (for one point harping, =0) φ φ 1 Initial amber after detensioning is used to indiretly hek the quality of the produt, for example, the level of prestress and other prodution issues. Camber at the time of girder shipping is sometimes required to be heked for ontratual purposes. Camber just before dek plaement and the elasti defletion due to dek weight are used to determine the elevation of the formwork supports at the edges of the top flange. Aurate measurements and alulations at this stage result in minimizing grinding of the dek to bring it to the required profile. a b Curvature diagram (for straight strand profile, urvature is onstant) Figure 1. Beam elevation showing general profile for a group of pretensioned strands. Figures: econstrut. A negative amber (downward defletion or sag) while the bridge is in servie may ause onern for inspetors and the publi and, if exessive, may have strutural and funtional impats as well. A number of state highway authorities (SHA) have speified that the final long-term amber due to all loads, exept live load, must be positive, that is, upward. L/ 38 ASPIRE, Spring 015
2 beam ends. Speified onrete strength at transfer is 6 ksi and at servie is 8.5 ksi. M e1 L L s M Me Equation 1, applied four times for the four groups of strands, yields a predited prestress-only amber Δip of 5.33 in. The groups are 3 strands that are = ft long, and three groups of four strands that are 1.1, 118.1, and ft long. The 1.5 ft quantity used to ompute the length for the 3 strand group is an allowane for averaging the effet of the 3 ft transfer length for the 0.6-in.-diameter strands. Figure. Bending moment diagram for beam in storage, note the onsiderable overhang. Figure: econstrut. At best, amber predition an have ±5% variability, but more realistially it an have ±50% variability. The predition is impated by things that are known within a narrow band of variability suh as the ross-setion dimensions, amount of prestress, and span length, whih are onsidered here to be deterministi variables. It is also impated by random variables, outside of the ontrol of the designer at time of design, suh as soure of aggregates, relative humidity and temperature of the ambient air, method of uring, method of detensioning, onditions of storage, and time elapsed between girder prodution and dek plaement. Calulation of Initial Camber Referene 1 gives a survey of the history of amber predition and proposes a method that an be programmed in a spreadsheet. Only two equations are required. Equation 1 is used to alulate initial amber due to prestress using a general profile of a group of pretensioned strands (Fig. 1). The equation is valid for straight and draped strands and for ases where debonding at the ends is utilized. The equation may be applied to the different types of strand groups, and then superposition used to ombine the individual results to determine the full effet. = φ1 ( b + )(a + b + ) + φ (3ab + b + 6a + 6b 3 ) 6 Eq. 1 ip + The distanes a, b, and are defined in Fig. 1. The urvatures φ 1 and φ are equal to P/ EI for Setions 1 and at the loation at whih prestress is effetive at the end of the girder (dimension a) and at midspan, respetively. The values of P, e, E, and I are the prestress fore, its eentriity, the onrete modulus of elastiity, and the ross setion moment of inertia, respetively, at the setion onsidered for the urvature alulation. The starting setion loation (at dimension a from the end of the girder) is affeted by length of debonding plus an allowane for transfer length. Equation is used to determine defletion due to beam weight (Fig. ). In reent years, long beams have required lifting, storage, and shipping with overhangs as long as 0 ft. The equation aounts for overhang length. gi 5Ls = (0.1M e1 + M + 0.1M e) Eq. 48EI For this equation, the length L s is length between supports during beam storage. Figure defines the moments in Eq. and their loations. The example in Referene 1 is used here for disussion purposes. Not all data are given here. The I-beam is 7 in. deep, 137 ft 1 in. long, and prestressed with forty-four 0.6-in.-diameter straight strands, 1 of whih are debonded in three equal groups for 6, 8, and 14 ft from the Equation is applied assuming a storage span of ft. The orresponding defletion is.3 in. The net predited self-weight amber is therefore = 3.01 in. Causes of Initial Camber Variability Many fators influene the value of amber at transfer of prestress, some of whih are random variables beyond the ontrol of the designer. Several of the more important fators are listed here: The modulus of elastiity of onrete. The omputed modulus of elastiity of onrete has been shown to vary from the measured value by % for onfidene between 10 and 90 perentiles, aording to the NCHRP study that proposed the aggregate orretion fator, K 1, whih now appears in Equation of the AASHTO LRFD Bridge Design Speifiations. The stiffness of aggregates plays an important role in the modulus variability. Thus, the results are dependent on the aggregate soure. Also, a designer who speifies 6 ksi onrete transfer strength is unlikely to get it mathed during prodution of all the beams in a projet. Curing versus ambient temperature. This fator an be very signifiant in the first 48 hours of onrete age. The onrete temperature may be as muh as 10 F above the ambient temperature beause of uring and ement hydration. This ould derease the tension in the strands by as muh as 0 ksi. This temporary differene may ause signifiant hanges in amber and prestress loss. 3 However, within about 7 hours, this temporary effet seems to dissipate. Loation of lifting inserts and storage supports. The effet of ASPIRE, Spring
3 1-1 Figure 3. Initial-amber data olleted by the PCI Fast Team from nine sites in eight states. The red lines show proposed ±50% ½ in. tolerane. Figure: PCI Fast Team with modifiation by econstrut. variation in support loations is illustrated using the example girder. If it is lifted and stored on supports that are 10 ft from the ends, the amber in the example used in the previous setion hanges by about 9%. If prestress is higher than the theoretial value by 5% and selfweight is lower by 5%, both of whih are quite plausible, the net amber in the example in the previous setion would inrease by 13%. Initial Camber Tolerane Limits Beause of the random variability of the influening parameters, it is diffiult to aurately predit initial amber immediately after strand detensioning. If the girder onrete is allowed to ool for 7 hours, predition auray may be most optimistially within ±5%. Aurate formulas, suh as Eq. 1 and, and values of the modulus of elastiity refleting aggregate type and onrete strength would be assumed to be used. However, the designer is not likely to know produer-speifi materials, environmental onditions, and prodution praties in advane. The PCI Tolerane Committee has been debating in reent years how to update the tolerane limits for amber in bridge beams that are given in PCI MNL-116 4, in order to aommodate reent hanges in tehnology. Conrete strengths in the 8 to 1 ksi range, 0.6-in.-diameter strands, and more effiient I-girder shapes have been in ommon use, resulting in pretensioned produts as long as 00 ft. A Fast Team was formed by the PCI Committee on Bridges and the Bridge Produers Committee to reommend adjustments to the urrent MNL-116 toleranes to aount for the reent hanges in pratie. Their reommendation is shown in Fig. 3. It essentially sets the tolerane limits on amber variane from the predited value at 0.1% of the produt length with an upper limit of 1½ in. and no lower limit. Even with this proposed removal of the urrent upper limit of 1 in., the Fast Team report indiated that the perentage of out-of-tolerane girders longer than 80 ft was still 1%, ompared to the urrent 37% level (using the 1 in. upper limit). Aordingly, the Fast Team stated, out of tolerane amber should not be a sole soure for rejetion. While this sentene is well intentioned and justified, it seems to be in onflit with the onept of tolerane enforement that is expeted in a tolerane manual. Proposed Initial Camber Tolerane Beause amber is an important quantity that an be easily measured, amber tolerane limits are expeted to ontinue to be required by most owners. Based on the author s experiene with this topi for nearly 40 years, and on reent disussions by PCI ommittees, produer groups, and state highway agenies, inluding Colorado, Washington, Iowa, and Pennsylvania, the following reommendations are proposed for initial amber of prestressed beams, whih differ from the reommendations of the PCI Fast Team: Initial amber should be measured 7 to 96 hours after beam onrete plaement and after the beam has been set on storage supports. This would allow for the internal onrete temperature to reah equilibrium with the ambient air and for the storage span to be set. Measurements should 40 ASPIRE, Spring 015
4 be made early in the morning when the girders should have a neutral thermal gradient. For predited amber 1 in., tolerane is ± ½ in. For predited amber > 1 in., tolerane is ±50% of the predited amber. Out-of-tolerane produts should be further investigated by qualified personnel to identify the presene of possible defiienies. Camber alone should not be the sole ause of rejetion. Camber Variability at Dek Plaement Camber predition at time of dek plaement is needed to establish elevations for beam seats and for formwork for the dek. This is neessary so that the top of road elevation and the overhead learane below the bridge are onsistent with design requirements. Conrete reep and shrinkage ause prestress to be lost. In addition, reep auses the beam to ontinue to amber with time. Creep and shrinkage are funtions of the onrete ingredients, setion dimensions, and environmental onditions. Furthermore, it is not known in advane how muh time will elapse between girder prodution and dek plaement. Camber does not always grow between initial storage onditions and dek plaement. This observation has reently been reported for relatively long beams. The reep multiplier for prestress effets (amber) is not as large as the reep multiplier for beam self-weight beause prestress ontinues to derease with time. For example, a 10 in. initial amber due to prestress multiplied by a 1.7 reep fator is 17 in. An 8 in. defletion due to beam self-weight multiplied by a.0 reep fator is 16 in. The net predited amber at dek plaement is 1 in. This is ompared to an initial amber of 10 8 = in. Methods of aurate predition of amber at time of dek plaement are summarized in the artile by Tadros et al. 1 Several states, in ollaboration with designers and preast produers, have developed their own reep multipliers to aount for amber growth between prestress release and dek plaement. It would seem reasonable to show upper and lower bound amber multipliers, based on loal prevailing onstrution and environmental onditions. For example, Washington State guidelines show a lower bound of 50% of the amber at 40 days, and an upper bound of 100% of the amber at 10 days. The author reommends a multiplier to be determined by eah preaster for the region served by their ompany. For example, Supplier X serving Western State Y would provide the owner with a lower bound and upper bound multipliers of 0.9 and.6 applied to initial amber to predit amber at time of dek plaement. The data presented in Fig. 4, whih has been supplied by Troy Jenkins of Northeast Prestressed Produts, illustrates amber variability at 10 days for girders produed by his ompany in several states in the Northeast. The figure shows that only a few points fall outside the proposed amber toleranes indiated by the red lines. It is suggested that the PCI Committee on Bridges and Bridge Produers Committee should onsider setting up uniform national guidelines for ahieving this important task. Aommodating Differenes There are two options for aommodating differenes between predited and measured amber at dek plaement. Measured amber larger than predited amber Assume for this disussion that 1-1 Figure 4. Measured amber at 10 days. Red lines show proposed ±50% ½ in. tolerane. Data: Northeast Prestressed Produts. ASPIRE, Spring
5 predited amber for a 150-ft-span beam is 3 in. while the measured amber is 6 in. The designer had allowed for a ast-in-plae onrete haunh of 1 in. above the top flange of the beam at midspan. The simplest solution is for the owner to allow raising the roadway by to 3 in. Alternatively, the girder seats ould be set to 3 in. lower than previously speified. This option would require appropriate preplanning. Measured amber smaller than predited amber Assume for this disussion that predited amber is 3 in. while the measured amber is 1.5 in. The seats may be raised to avoid infringing on overhead learane below the bridge, if this is a fator, and to avoid exessive haunh onrete. Also, adequate drainage needs to be heked to avoid water ponding on the bridge. Referenes 1. Tadros, Maher K., F. Fawzy, and K. Hanna Preast, Prestressed Girder Camber Variability, PCI Journal, Vol. 56, No. 1: Preast, Prestressed Conrete Institute (PCI).. Tadros, M. K., N. Al-Omaishi, S. J. Seguirant, and J. Gallt Prestress Losses in High-Strength Conrete Bridge Girders. Report 496. National Cooperative Highway Researh Program (NCHRP). Washington, DC: Transportation Researh Board. 3. Davison, Bill Predition of Time-Dependent Stresses and Defletions in Prestressed Conrete Girders from Start of Fabriation to End of Servie Life, M.S. Degree Thesis, University of Washington, Seattle, WA, 013, Advisors John Stanton and Mar Eberhard, 158 pp. 4. PCI Manual for Quality Control for Plants and Prodution of Strutural Preast Conrete Produts. MNL-116, 4th edition: PCI. Dr. Maher Tadros is prinipal with econstrut in Omaha, Neb. MOVE THE HEAVYWEIGHTS! 1 Timber Lane Marlboro NJ USA tel: (73) fax: (73) sales@hilmanrollers.om 4 ASPIRE, Spring 015
Proposal for a new shear design method
Chapter 6 Proposal for a new shear design method The behaviour of beams failing in shear has been studied in the previous hapters, with speial attention paid to high-strength onrete beams. Some aspets
More informationExample 24.3 Flexural Strength of Prestressed Member Using Approximate Value for f ps
Example 24.3 Flexural Strength of Prestressed Member Using Approximate Value for f ps Calulate the nominal moment strength of the prestressed member shown. f = 5000 psi f pu = 270,000 psi (low-relaxation
More informationPrestress Loss Distributions along Simply Supported Pretensioned Concrete Beams
Eletroni Journal o Strutural Engineering 16(1) 016 Prestress Loss Distributions along Simply Supported Pretensioned Conrete Beams J. Kent Hsiao Department o Civil and Environmental Engineering, Southern
More informationWATER WITHIN LIGHTWEIGHT AGGREGATE CONCRETE AND ITS RELATION TO AUTOGENOUS SHRINKAGE
WATER WITHIN LIGHTWEIGHT AGGREGATE CONCRETE AND ITS RELATION TO AUTOGENOUS SHRINKAGE S.A. Kristiawan Department of Civil Eng.Sebelas Maret University, e-mail: sa_kristiawan@uns.a.id Senot Sangadji Department
More informationPredicted vs Measured Initial Camber in Precast Prestressed Concrete Girders
University of Arkansas, Fayetteville ScholarWorks@UARK Civil Engineering Undergraduate Honors Theses Civil Engineering 5-2017 Predicted vs Measured Initial Camber in Precast Prestressed Concrete Girders
More informationPrestress Loss Distributions along Simply Supported Pretensioned Concrete Beams
Southern Illinois University Carbondale OpenSIUC Publiations Department o Civil and Environmental Engineering 017 Prestress Loss Distributions along Simply Supported Pretensioned Conrete Beams Jen-kan
More informationFinite Element Modeling of Pre-Stressed Hollow Core Slabs
Current Siene International Volume : 04 Issue : 04 Ot.-De. 2015 Pages :596-603 Finite Element Modeling of Pre-Stressed Hollow Core Slabs 1 Ali N. Deeb, 2 M. Abou Zeid Tarkhan and 3 E. M. El-Tehewy 1 Syrian
More informationEXPERIMENTAL STUDY ON LINK SLAB FOR HIGHWAY GIRDERS
การประช มว ชาการว ศวกรรมโยธาแห งชาต คร งท ๑๐ ชลบ ร ๒ ๔ พฤษภาคม ๒๕๔๘ EXPERIMENTAL STUDY ON LINK SLAB FOR HIGHWAY GIRDERS Tayagorn Charuhaimontri 1 Ekasit Limsuwan 2 1 Ph.D.Student, Department of Civil Engineering,
More informationFull Scale Load Testing of Selected RG4 Supporting Beam
Full Sale Load Testing of Seleted RG4 Supporting Beam BPEX PROJECT Maptaphut, Rayong Final Report by Civil and Environmental Engineering Design and Consulting Servie Mahidol University Applied and Tehnologial
More informationMechanical Properties of High-Strength Concrete Manish Kumar 1, A.M. ASCE; Zhaoyu Ma 2 ; Moses Matovu 2
1.1 Introdution Mehanial Properties of High-Strength Conrete Manish Kumar 1, A.M. ASCE; Zhaoyu Ma 2 ; Moses Matovu 2 Mehanial properties of High-Strength Conrete (HSC) an be divided in two groups as shortterm
More informationContinuous temperature measurements on the pouring stand for casting moulds
ARCHIVES of FOUNDRY ENGINEERING Published quarterly as the organ of the Foundry Commission of the Polish Aademy of Sienes ISSN (897-330) Volume 8 Issue /008 75 80 5/ Continuous temperature measurements
More informationFINITE ELEMENT MODELLING OF STEEL-CONCRETE COMPOSITE BEAMS STRENGTHENED WITH PRESTRESSED CFRP PLATE
FINITE ELEMENT MODELLING OF STEEL-CONCRETE COMPOSITE BEAMS STRENGTHENED WITH PRESTRESSED CFRP PLATE H.Y. Omran 1, P. Zangeneh 2, and R. EL-Haha 3 1 PhD student, Department of Civil Engineering, University
More informationSuggested Changes to NZS3101:2006 with Amendments 1 and 2
1 Suggested Changes to NZS3101:2006 with Amendments 1 and 2 Rihard Fenwik and Dene Cook Introdution NZS 3101: 2006 Conrete Strutures Standard is a design ode published by Standards New Zealand. Sine the
More information7001 Diamond Snap-Form ICF Code Considerations With the multitude of lightweight onrete forming systems in the onstrution market, building offiials are raising questions about ode ompliane and/or ode evaluation
More informationTensile Force Evaluation of Unbonded PT Bars in Precast Concrete Columns
Fédération Internationale du Béton Proeedings of the 2 nd International Congress ID 2-32 Session 2 Tensile Fore Evaluation of Unbonded PT Bars in Preast Conrete Columns Tani, M., Nishiyama, M. Department
More informationPost-Tensioned Two-Way Slab
The Medial Oie Building Malvern, PA 13 Post-Tensioned Two-Way Slab Introdution The Filigree beam system reates a thin lightweight loor system that leaves plenty o open plenum spae or mehanial and eletrial
More informationEffect of Variation of Fuel Composition on Gas Turbine Off-Design Performance
Applied Mehanis and Materials Submitted: 2014-08-28 ISSN: 1662-7482, Vol. 666, pp 194-198 Aepted: 2014-08-28 doi:10.4028/www.sientifi.net/amm.666.194 Online: 2014-10-20 2014 Trans Teh Publiations, Switzerland
More informationIndeterminate Prestressed Structures
Indeterminate Prestressed Strutures Introdution Use of ontinuous sstems results in redution of moments and stresses at midspans. Shallower members are used Stiffer than simpl supported members of equal
More informationPrediction of Temperature and Aging Effects on the Properties of Concrete
Predition of Temperature and Aging Effets on the Properties of Conrete Jin-Keun Kim 1* and Inyeop Chu 1 1 KAIST, Republi of Korea * E-mail: kimjinkeun@kaist.a.kr ABSTRACT For the sustainable onrete strutures,
More informationTRANSLATION OF MEASURED VEHICULAR WEIGHTS INTO DESIGN LOADS TO BE USED FOR BRIDGE ENGINEERING
7th International Symposium on Heavy Vehile Weights & Dimensions Delft. The Netherlands. June 16-2.22 TRANSLATION OF MEASURED VEHICULAR WEIGHTS INTO DESIGN LOADS TO BE USED FOR BRIDGE ENGINEERING ABSTRACT
More informationLIGHTWEIGHT CONCRETE MATERIAL PROPERTIES FOR STRUCTURAL DESIGN. Henry G. Russell, Henry G. Russell, Inc., Glenview, IL
LIGHTWEIGHT CONCRETE MATERIAL PROPERTIES FOR STRUCTURAL DESIGN Henry G. Russell, Henry G. Russell, In., Glenview, IL ABSTRACT This paper ontains a ompilation and synthesis of researh relating to lightweight
More informationEnergy Savings from Increased Preventive Maintenance on Indiana Highways
TRANSPORTATION RESEARCH RECORD 112 27 Energy Savings from Inreased Preventive Maintenane on Indiana Highways EssAM A. SHARAF AND KuMARES C. SINHA In this paper are desribed the development of trade-off
More informationBuildup Factors Calculation for a 1-MeV Point Isotropic Source in Iron, Concrete, and. Water. Skyler Butler, Maria Pinilla
Buildup Fators Calulation for a 1-MeV Point Isotropi Soure in Iron, Conrete, and Water Skyler Butler, Maria Pinilla Abstrat This experiment alulates the buildup fators for 1-MeV point isotropi soure of
More informationSDI-C-2011 Standard for Composite Steel Floor Deck-Slabs 30 November General
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 1. General SDI-C-2011 Standard for Composite Steel Floor Dek-Slabs 30 November
More information4.1 Design of Members
restressed Conrete Strutures Dr. Amlan K Sengupta and ro. Devdas Menon 4.1 Design o Members This setion overs the ollowing topis Calulation o Demand Design o Setions or Axial Tension Introdution The design
More informationR. W. Barnes, N. H. Burns, and M. E. Kreger Research Report
Tehnial Report Doumentation Page 1. Report No. 2. Government Aession No. 3. Reipient s Catalog No. FHWA/TX-02/1388-1 4. Title and Subtitle 5. Report Date Development Length of 0.6-Inh Prestressing Strand
More informationPermanent Link:
Citation: Boswell, Brian and Chandratilleke, Tilak. 2009. Sustainable Metal Cutting, in TIC-STH ommittee (ed), 2009 IEEE Toronto International Conferene Siene and Tehnology for Humanity, Sep 26 2009. Ryerson
More informationComposite Steel Floor Deck-Slabs
AMERICAN NATIONAL STANDARDS / STEEL DECK C - 2017 Standard for Composite Steel Floor Dek-Slabs opyright 2017 steel dek institute 1. General AMERICAN NATIONAL STANDARDS / STEEL DECK 1.1 Sope: A. This Standard
More informationFatigue and Creep-Fatigue Testing of Bellows at Elevated Temperature
S. Yamamoto K. Isobe S. Ohte Mehanial Engineering Laboratory, Researh and Development Center. N. Tanaka S. Ozaki Nulear Engineering Laboratory, Nulear Energy Group. K. Kimura Advaned Reator Engineering
More informationPrecast, prestressed girder camber variability
Precast, prestressed girder camber variability Maher K. Tadros, Faten Fawzy, and Kromel E. Hanna Camber variability is essential for design, fabrication, and construction. Although not always accurate,
More informationAccepted Manuscript. Factors affecting moment redistribution at ultimate in continuous beams prestressed with external CFRP tendons
Aepted Manusript Fators affeting moment redistribution at ultimate in ontinuous beams prestressed with external CFRP tendons Tiejiong Lou, Sergio M.R. Lopes, Adelino V. Lopes PII: S1359-8368(14)00205-4
More informationLOW FREQUENCY BUCKETS FOR INDUSTRIAL STEAM TURBINES by
LOW FREQUENCY BUCKETS FOR INDUSTRIAL STEAM TURBINES by Firm L. Weaver Engineering Consultant Sun City Center, Florida Firm L. Weaver graduated from Roanoke Coll ege, in Salem, Virginia, with a B.S. degree
More informationAnalysis of geopolymer concrete columns
Analysis of geopolymer onrete olumns Prabir Kumar Sarker, Leturer, Department of Civil Engineering, Curtin University of Tehnology, Perth, Western Australia, Phone: +61 8 9266 7568, Fax: +61 8 9266 2681,
More informationREVENUE SHARING CONTRACT OR WHOLESALE PRICE CONTRACT? ANALYTICAL RESULTS FROM VARIOUS CHANNEL POWER ARRANGEMENTS IN A TOURISM SUPPLY CHAIN
REVENUE SHARING CONTRACT OR WHOLESALE PRICE CONTRACT? ANALYTICAL RESULTS FROM VARIOUS CHANNEL POWER ARRANGEMENTS IN A TOURISM SUPPLY CHAIN n, College of Business, Washington State University, Wilson Road,
More information3.1 Analysis of Members under Axial Load
3.1 Analysis of Members under Axial Load This setion overs the following topis. Introdution Analysis at Transfer Analysis at Servie Loads Analysis of Ultimate Strength Analysis of Behaviour Notations Geometri
More informationBridge Element Deterioration Rates
TRANSPORTATION RESEARCH RECORD 149 9 Bridge Element Deterioration Rates lmad J. ABED-AL-RAHIM AND DAVID W. JOHNSTON Prediting the deterioration rates of bridge elements is an important?ponent of any ridge
More informationPROPOSAL OF A STANDARD FOR SEISMIC DESIGN OF CONFINED MASONRY BUILDINGS
Institute of Industrial Siene, University of Tokyo Bulletin of ERS, No. 37 PROPOSAL OF A STANDARD FOR SEISMIC DESIGN OF CONFINED MASONRY BUILDINGS Angel SAN BARTOLOME 1, Daniel QUIUN 1 and Paola MAYORCA
More informationEconomic Assessment of Intensive Culture
Reprodued from JOURNAL OF FORESTRY, Vol. 76, No. 11, November 1978, by the FOREST SERVICE, U.S. Department of Agriulture, for offiial use. About This File:,. lhis file was reated by sanning the printed
More informationFinal Report PERFORMANCE-RELATED SPECIFICATIONS FOR CONCRETE BRIDGE SUPERSTRUCTURES FHWA/IN/JTRP-2001/8. Volume 3 Nonmetallic Reinforcement
Final Report PERFORMANCE-RELATED SPECIFICATIONS FOR CONCRETE BRIDGE SUPERSTRUCTURES FHWA/IN/JTRP-2001/8 Volume 3 Nonmetalli Reinforement Robert J. Frosh Professor of Civil Engineering Prinipal Investigator
More informationJ. A. Avila Institute of Engineering, National University of Mexico (UNAM), Mexico. Abstract. 1 Introduction
High Performane Strutures and Materials V 99 Prinipal results of the inelasti seismi performane of a 17-story RC building loated in the soft-soil area in Mexio City with normal-strength onrete and with
More informationProject Summary Determination of Capillary Pressure-Saturation Curves Involving TCE, Water and Air for a Sand and a Sandy Clay Loam
United States Environmental Protetion Ageny Researh and Development Robert S. Kerr Environmental Researh Laboratory Ada, OK 70 EPA/00/SR-9/005 Marh 99 Projet Summary Determination of Capillary Pressure-Saturation
More informationten reinforced concrete construction Concrete Concrete Materials Concrete Construction columns beams slabs domes footings
APPLID ACHITCTURAL STRUCTURS: STRUCTURAL ANALYSIS AND SYSTMS DR. ANN NICHOLS FALL 01 leture ten Conrete olumns beams slabs domes ootings http://nisee.berkeley.edu/godden reinored onrete onstrution http://nisee.berkeley.edu/godden
More informationNew York. Performance of Cable Guiderail in WEI-SHIH YANG, LUIS JULIAN BENDANA, NICHOLAS J. BRUNO, AND WAYNE D. KENYON
TRANSPORTATON RESEARCH RECORD 1419 9 Performane of Cable Guiderail in New York WE-SHH YANG, LUS JULAN BENDANA, NCHOLAS J. BRUNO, AND WAYNE D. KENYON Cale guiderail ith insffiient tension may deflet -exessively
More informationTHE ENERGY DISSIPATION EFFECTS OF REDUNDANT MEMBERS IN SILOS UNDER EARTHQUAKES
269 THE ENEGY DISSIPATION EFFECTS OF EDUNDANT MEMBES IN SILOS UNDE EATHQUAKES Li Zhiming 1 and Geng Shujiang 1 SUMMAY An analytial study is made the response to strong base motion reinfored onrete silo
More informationPerformance of Recycled Asphalt Concrete Overlays in Southwestern Arizona
3 TRANSPORTATION RESEARCH RECORD 1427 Performane of Reyled Asphalt Conrete Overlays in Southwestern Arizona MusTAQUE HossAIN, DWIGHT G. METCALF, AND LARRY A. SoFIELD Reyled asphalt onrete overlay is a
More informationA study on local stresses of corrugated steel webs in PC bridges under prestressing
A study on loal stresses of orrugated steel webs in PC bridges under prestressing Shogo MORI *, Takao MIYOSHI **, Hisato KATOH *** Nobuo NISHIMURA ****, Satoshi NARA ***** Abstrat Generally, seldom orrugated
More informationOptimizing Traffic Diversion Around Bottlenecks
22 Optimizing Traffi Diversion Around Bottleneks YI-CHIN HU and PAUL SCHONFELD ABSTR.CT A traffi simulation and optimization model has been developed to analyze traffi flow in large networks with severe
More informationCorrosion of reinforcing steel is widely accepted as the
Strength eterioration of Reinfored Conrete Columns Exposed to Chloride Attak R. Greo, G.C. Marano Abstrat This paper fouses on reinfored onrete olumns load arrying apaity degradation over time due to hloride
More informationNumerical Modeling and Experimental Investigation of the Failure Modes of the Cellular Foam Sandwich Structures
Journal of Metals, Materials and Minerals, Vol.18 No.2 pp.111-115, 2008 Numerial Modeling and Experimental Investigation of the Failure Modes of the Cellular Foam Sandwih Strutures Jörg FELDHUSEN 1, Sirihai
More informationSteel. Members. in medium to. composite. provisions for. the available. b) strength of. design,
Chapter 13 Steel Conrete Composite Strutural Members 13.1 General Provisions for Steel Conrete Composite Strutural Members This setion states the sope of the speifiation, summarizess referened speifiations,
More informationYield curvature for seismic design of circular reinforced concrete columns
University of Wollongong Researh Online Faulty of Engineering - Papers (Arhive) Faulty of Engineering and Information Sienes 1 Yield urvature for seismi design of irular reinfored onrete olumns M Neaz
More informationSystems & Services Certification SGS 53,000, 1000
CSR July 28, 2009 SGS Systems & Servies Certifiation SGS SGS SGS 1878 SGS 140 53,000, 1000 - Europe, Middle East & Afria: 24 400 employees - Amerias: 12 100 employees - Asia/Paifi: 16 500 employees SGS,
More informationSEISMIC RETROFIT USING CONTINUOUS FIBER SHEETS
SEISMIC RETROFIT USING CONTINUOUS FIER SHEETS Yasuhiro MATSUZAKI 1, Katsuhiko NAKANO, Shigeru FUJII 3 And Hiroshi FUKUYAMA 4 SUMMARY The researh on seismi retrofit of RC members using ontinuous fiber sheets
More informationComparison Study of Connector and Tubing Blow-Off Line
PROCEEDINGS Comparison Study of Connetor and Tubing Blow-Off Line Pressures Jerry D. Leaf, Charles Dyson, Robert Emerson UCLA Medial Center, Department of Surgery, Division of Thorai Surgery Abstrat The
More informationEXPERIMENTAL INVESTIGATION OF ECCENTRIC REINFORCED CONCRETE BEAM-COLUMN-SLAB CONNECTIONS UNDER EARTHQUAKE LOADING
13 th World Conferene on Earthquake Engineering Vanouver, B.C., Canada August 1-6, 24 Paper No. 215 EXPERIMENTAL INVESTIGATION OF ECCENTRIC REINFORCED CONCRETE BEAM-COLUMN-SLAB CONNECTIONS UNDER EARTHQUAKE
More informationESTIMATION OF FRACTURE TOUGHNESS OF THE OXIDE SCALES. Jozef HRABOVSKÝ, Petr LOŠÁK, Jaroslav HORSKÝ
ESTIMATION OF FRACTURE TOUGHNESS OF THE OXIDE SCALES Jozef HRABOVSKÝ, Petr LOŠÁK, Jaroslav HORSKÝ Heat Transfer and Fluid Flow Laboratory, Faulty of Mehanial Engineering, VUT Brno, Tehniká 2, 616 69 Brno,
More informationSHEAR CAPACITY FOR PRESTRESSED-PREFABRICATED HOLLOW CORE CONCRETE SLABS,WITHOUT SHEAR REINFORCEMENT
SHEAR CAPACTY FOR PRESTRESSED-PREFABRCATED HOLLOW CORE CONCRETE SLABS,WTHOUT SHEAR RENFORCEMENT A B S T R A C T PNTEA Augustin, Tehnial University of Cluj-Napoa, e-mail: augustinpintea@yahoo.om Euroode
More informationWeb buckling strength of beam-to-column connections, September 1970 (74-1) PB / AS
Lehigh University Lehigh Preserve Fritz Laboratory Reports Civil and Environmental Engineering 1970 Web bukling strength of beam-to-olumn onnetions, September 1970 (74-1) PB 234 621/ AS W. F. Chen I. J.
More informationExperiment Station. Department of Soil and Crop Sciences
Tehnial Bulletin TB06-03 August 2006 Ag riultural Experiment Station College of Agriultural Sienes Department of Soil and Crop Sienes Western Colorado Researh Center Organi Alternatives for Weed Control
More informationExperimental and Theoretical Deflections of Hybrid Composite Sandwich Panel under Four-point Bending Load
Civil Engineering Dimension, Vol. 19, No. 1, Marh 017, 9-5 ISSN 1410-950 print / ISSN 1979-570X online DOI: 10.9744/CED.19.1.9-5 Experimental and Theoretial Defletions of Hybrid Composite Sandwih Panel
More informationMODELING FLEXIBLE PACKAGE/GRANULAR MATERIAL INTERATION THROUGH COMBINATION OF DISCRETE ELEMENT METHOD (DEM) AND FINITE ELEMENT METHOD (FEM)
MODELING FLEXIBLE PACKAGE/GRANULAR MATERIAL INTERATION THROUGH COMBINATION OF DISCRETE ELEMENT METHOD (DEM) AND FINITE ELEMENT METHOD (FEM) Wenbo Xu, Pavan Valavala, Mark Mirgon, Sam Crabtree, Lori Kardos,
More informationThe influence of pallets on the behaviour and design of steel drive-in storage racks - Part II Design
University of Wollongong Researh Online Faulty of Engineering and Information Sienes - Papers: Part A Faulty of Engineering and Information Sienes 2013 The influene of pallets on the behaviour and design
More informationAPPLICATION OF BASE ISOLATION IN HIGH VOLTAGE ELECTRICAL EQUIPMENT.
The th World Conferene on Earthquake Engineering Otober 7, 8, Beijing, China APPLICATION OF BASE ISOLATION IN HIGH VOLTAGE ELECTRICAL EQUIPMENT ABSTRACT: Han Junke, Zhang Chunlei, Yang Fengli, Cao Meigen
More informationStructural Concrete Design
50 Strutural Conrete Design Amy Grider Purdue University Julio A. Ramirez Purdue University Young Mook Yun Purdue University 50.1 Properties of Conrete and Reinforing Steel Properties of Conrete Lightweight
More informationDEVELOPMENT AND INVESTIGATION OF A SYMMETRIC INDUCTION HEATING UNIT FOR SPHERICAL SHAPE METAL WARE
Journal of Chemial Sergey Tehnology S. Titov, Vitor and Metallurgy, N. Meshheryakov 53, 5, 2018, 1009-1016 DEVELOPMENT AND INVESTIGATION OF A SYMMETRIC INDUCTION HEATING UNIT FOR SPHERICAL SHAPE METAL
More informationA flush collector beam end plate is used to allow for the placement of the floor deck on top of the collector beam.
EARTHQUAKE Eentrially Braed Frames with Removable Links Design Methodology Author: Kevin Cowie a, Alistair Fussell a, Martin Wong a, Charles Clifton b, Dmitry Volynkin b Affiliation: a. Steel Constrution
More informationTests on Reinforced Concrete Slabs with Pre-stressing and with Transverse Reinforcement under Impact Loading
20th International Conferene on Strutural Mehanis in Reator Tehnology (SMiRT 20) Espoo, Finland, August 9-14, 2009 SMiRT 20-Division 5, Paper 2015 Tests on Reinfored Conrete Slabs with Pre-stressing and
More informationEITF ABSTRACTS. To take advantage of new capabilities in electronic commerce and advances in computer
EITF ABSTRACTS Issue No. 97-13 Title: Aounting for Costs Inurred in Connetion with a Consulting Contrat or an Internal Projet That Combines Business Proess Reengineering and Information Tehnology Transformation
More informationLimit states for the damage assessment of bridges supported on LRB bearings
Journal of Physis: Conferene Series PAPER OPEN ACCESS Limit states for the damage assessment of bridges supported on LRB bearings To ite this artile: M Jara et al 05 J. Phys.: Conf. Ser. 68 0046 View the
More informationCIVL 1112 Reinforced Concrete Beam - Example 3 1/5
CIVL Reinfored Conrete Beam - Example /5 Let s use the failure models to predit the ultimate strength-toweight (SWR) of one of our reinfored onrete eams from la Reinforing ars are denoted y the ar numer.
More informationExperimental Study of a New Type Buckling-Restrained Brace. Abstract
Experimental Study of a New Type Bukling-Restrained Brae S. G. CHENG, X.X. KONG AND K.H. LUO Institute of Earthquake Engineering, China Aademy of Building Researh Abstrat The steel ore and unbonding agent
More informationSeismic Fragility Assessment of Transmission Towers via Performance-based Analysis
Seismi Fragility Assessment of Transmission Towers via Performane-based Analysis Liyu XIE, Jue TANG, Hesheng TANG & Qiang XIE Institute of Strutural Engineering and Disaster Redution, College of Civil
More informationPrestressed Concrete Pavement: Instrumentation, Behavior, and Analysis of Horizontal Movements
38 TRANSPORTATION RSARCH RCORD 1286 Prestressed Conrete Pavement: Instrumentation, Behavior, and Analysis of Horizontal Movements LLIOTT DAVID MANDL, ND H. BURNS, AND B. FRANK MCULLOUGH The long-term work
More information1 INTRODUCTION. Akbar Haghinejad Mahdi Nematzadeh *
916 Three-Dimensional Finite Element Analysis of Compressive Behavior of Cirular Steel Tube-Confined Conrete Stub Columns by New Confinement Relationships Abstrat This paper presents a nonlinear analysis
More informationCreep Analysis of Aluminum Alloy Disk Experiment for High Speed Energy Storage Flywheel
Creep Analysis of Aluminum Alloy Disk Experiment for High Speed Energy Storage Flywheel YangXU, HanYU, ZupeiSHEN Tsinghua Univ. CHINA Abstrat: In order to ahieve higher speed and higher energy density,
More informationNUMERICAL SIMULATION OF BEHAVIOUR OF REINFORCED CONCRETE STRUCTURES CONSIDERING CORROSION EFFECTS ON BONDING
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 NUMERICAL SIMULATION OF BEHAVIOUR OF REINFORCED CONCRETE STRUCTURES CONSIDERING CORROSION EFFECTS ON BONDING C.Q. Li 1, S.T. Yang 2 and M. Saafi 3 ABSTRACT
More informationBEHAVIOR OF PRESTRESSED SIMPLE AND CONTINUOUS PARTIALLY COMPOSITE STEEL-CONCRETE BEAMS
ACTA TECHNICA CORVINIENSIS Bulletin of Engineering Tome IX [2016], Fasiule 3 [July September] ISSN: 2067 3809 1.Mohamed A. A. EL-SHAER, 2. Shymaa M. MUKHTAR BEHAVIOR OF PRESTRESSED SIMPLE AND CONTINUOUS
More informationUSE OF STEEL FIBER REINFORCED CONCRETE IN THIN SHELL STRUCTURES: EVALUATION OF FIBER PERFORMANCE THROUGH TESTING OF SHELL SPECIMENS
Computational Methods for Shell and Spatial Strutures IASS-IACM 2000 M. Papadrakakis, A. Samartin and E. Onate (Eds.) ISASR-NTUA, Athens, Greee 2000 USE OF STEEL FIBER REINFORCED CONCRETE IN THIN SHELL
More informationInternational Journal of Research (IJR) e-issn: , p- ISSN: X Volume 3, Issue 01, January 2016
International Journal of Researh (IJR) Available at http://internationaljournalofresearh.org Study of failure probability by deterministi method reliability-strength applied to metal ables intended for
More informationMARKET STRUCTURE AND PRODUCTIVITY: A CONCRETE EXAMPLE. Chad Syverson. Working Paper 10501
MARKET STRUCTURE AND PRODUCTIVITY: A CONCRETE EXAMPLE Chad Syverson Working Paper 10501 NBER WORKING PAPER SERIES MARKET STRUCTURE AND PRODUCTIVITY: A CONCRETE EXAMPLE Chad Syverson Working Paper 10501
More informationTwo-Way Flat Slab (Concrete Floor with Drop Panels) System Analysis and Design
Two-Way Flat Slab (Conrete Floor with Drop Panels) System Analysis and Design Two-Way Flat Slab (Conrete Floor with Drop Panels) System Analysis and Design Design the onrete floor slab system shown below
More informationEnergy Saving Opportunities through Heat Recovery from Cement Processing Kilns: A Case Study
Energy Saving Opportunities through Heat Reovery from Cement Proessing Kilns: A Case Study I. I. AL-HINTI a, A. AL-GHANDOOR b, A. AL-NAJI, M. ABU-KHASHABEH, M. JOUDEH, M. AL-HATTAB a Department of Mehanial
More informationFinite Element Analysis of sustainable and deconstructable semi-rigid beam-tocolumn. composite joints
ICCM214 28-3 th July, Cambridge, England Finite Element Analysis of sustainable and deonstrutable semi-rigid beam-toolumn omposite joints *Abdolreza Ataei 1, Mark A. Bradford 2 1,2 Centre for Infrastruture
More informationComparison of Large-Truck Travel Estimates from Three Data Sources
5 TRANSPORTATION RESEARCH RECORD 147 Comparison of Large-Truk Travel Estimates from Three Data Soures DAWN L. MASSIE, KENNETH L. CAMPBELL, AND DANIEL F. BLOWER The number of miles traveled eah year by
More informationEstimation of yield curvature for direct displacement-based seismic design of RC columns
Universit of Wollongong Researh Online Fault of Engineering - Papers (Arhive) Fault of Engineering and Information Sienes 8 Estimation of ield urvature for diret displaement-based seismi design of RC olumns
More informationCoordinating strategy of supply chain contract based on price discount and quantity buyback
ISSN 1816-6075 (Print), 1818-0523 (Online) Journal of System and Management Sienes Vol. 1 (2011) No. 4, pp. 19-29 Coordinating strategy of supply hain ontrat based on prie disount and quantity buybak Ping
More informationACI Structural Journal / July-August 1997
Shamim A. Sheikh is a professor of ivil engineering at the University of Toronto. He is hairman of joint ACI-ASCE Committee 441, Reinfored Conrete Columns, a member of joint ACI-ASCE Committee 442, Response
More informationDesign of Corrugated Metal Box Culverts
Transportation Researh Reord 18 33 Design of Corrugated Metal Box Culverts J. M. DUNCAN, R. B. SEED, and R. H. DRA WSKY ABSTRACT Corrugated metal box ulverts provide large ross-setional areas for water
More information30th Conference on OUR WORLD IN CONCRETE & STRUCTURES: August 2005, Singapore. Article Online Id:
EXPERIMENTAL RESEARCH ON JOINTS OF PRESTRESSED CONCRETE BEAM AND COMPOSITE CONCRETE COLUMN WITH CORE OF CONCRETE FILLED STEEL TUBE UNDER LOW-CYCLIC REVERSED LOADING Deng Zhi-heng*, Guangxi University,
More informationSTUDY ON THE MECHANICAL PROPERTIES OF THE FLY ASH GEOPOLYMER CONCRETE
International Journal of Civil Engineering and Tehnology (IJCIET) Volume 8, Issue 3, Marh 2017, pp. 950 957 Artile ID: IJCIET_08_03_095 Available online at http://www.iaeme.om/ijciet/issues.asp?jtype=ijciet&vtype=8&itype=3
More informationLaboratory Investigation of Properties of Asphalt-Rubber Concrete Mixtures
TRANSPORTATION RESEARCH RECORD 1417 93 Laboratory Investigation of Properties of Asphalt-Rubber Conrete Mixtures TAISIR S. l
More informationGenerating Light from Stoves using a Thermoelectric Generator
Generating Light from Stoves using a Thermoeletri Generator Dan Mastbergen, dmast@engr.olostate.edu Dr. Bryan Willson, Bryan.Willson@olostate.edu Engines and Energy Conversion Laboratory Department of
More informationDimensions of propulsion shafts and their permissible torsional vibration stresses
(Feb 2005) (orr.1 Mar 2012) (orr.2 Nov 2012) (Rev.1 Aug 2014) (Rev.2 Apr 2015) Dimensions of propulsion shafts and their permissible torsional vibration stresses.1 Sope This UR applies to propulsion shafts
More informationDetection of empty grate regions in firing processes using infrared cameras
11 th International Conferene on Quantitative InfraRed Thermography Detetion of empty grate regions in firing proesses using infrared ameras by J. Matthes*, P. Waibel* and H.B. Keller* *Institute for Applied
More informationShear Transfer Strength Evaluation for Ultra-High Performance Fiber Reinforced Concrete
Shear Transfer Strength Evaluation for Ultra-High Performane Fiber Reinfored Conrete Ji-hyung Lee, and Sung-gul Hong Abstrat Ultra High Performane Fiber Reinfored Conrete (UHPFRC) is distinguished from
More informationKeywords: Greenhouse; Thermal performance; Water pipes heating; Infrared radiation; Energy balance; Heating efficiency
International Symposium Greensys 7 "High Tehnology for Greenhouse system Management" Naples Italy, 4-6 Otober 7 Investigation of the Potential of Infrared-radiation (IR) to Redue Energy Consumption in
More informationTEMPERATURE ADAPTIVE CONTROL USING THE ADDITIVE MANUFACTURING FOR INJECTION MOLDING POLYMERIC PRODUCTS
5 th International Conferene Advaned Composite Materials Engineering COMAT 2014 16-17 Otober 2014, Braşov, Romania TEMPERATURE ADAPTIVE CONTROL USING THE ADDITIVE MANUFACTURING FOR INJECTION MOLDING POLYMERIC
More informationHenley Business School at Univ of Reading. Chartered Institute of Personnel and Development (CIPD)
MS in International Human Resoure Management (full-time) For students entering in 2013/4 Awarding Institution: Teahing Institution: Relevant QAA subjet Benhmarking group(s): Faulty: Programme length: Date
More informationCREEP BEHAVIOUR OF GEOMETRICALLY NONLINEAR SOFT CORE SANDWICH PANELS
20 th International Conferene on Composite Materials CRP BHAVIOUR OF GOMTRICALLY NONLINAR SOFT COR SANDWICH PANLS hab Hamed 1 and Yeoshua Frostig 2 1 Centre for Infrastruture ngineering and Safety, Shool
More informationFeed-Time Distribution in Pneumatic Feeding of Softwood Seedlings
Journal of Forest Engineering 49 FeedTime Distribution in Pneumati Feeding of Softwood Seedlings Ulf Hallonborg The Forestry Researh Institute of Sweden Uppsala, Sweden ABSTRACT Long seedling feed times
More information