Keywords: Continuous Plate Girder, H-Girder, AASHTO-2002, ASCE-02, UBC-1997, STAAD, Pro Software.

Transcription

1 ISSN Vol.03,Issue.06, May-014, Pages: Study on Continuous Plate Girder Highway Bridge with Dynamic Approach ZIN MAR OO Research Scholar, Dept of Civil Engineering, Mandalay Technological University, Mandalay, Myanmar, Astract: The main purpose of this study is to analyze and design of continuous plate girder highway ridge. The detail analysis and design of ridge with the application of STAAD.Pro software is presented in this study. The total length of ridge is 600 feet and the ridge consists of a 300 feet central span and 150 feet side spans. Total width of ridge surface is 30 feet, roadway width is 4 feet and sidewalk is 3 feet at each side. In the proposed H-girder ridge, there are 458 memers and 07 nodes are presented. All proale dead load, live loads including AASHTO HS 0-44 truck loading and lane load, temperature load, impact load, wind load and seismic load for zone-4 are considered y ASCE-0, AASHTO-00 and UBC Section of steel memers is used with W-shapes. The material properties of steel are A57 Grade 50 steel and reinforcing steel Grade 40 for sla design. Design of ridge sla is manually calculated with the requirements of specification. Design checking are done for floor eam, cross eam and racing from the maximum force of output result of STAAD.Pro software. Deflection is also checked for the staility of the ridge according to AASHTO specification. Keywords: Continuous Plate Girder, H-Girder, AASHTO-00, ASCE-0, UBC-1997, STAAD, Pro Software. I. INTRODUCTION Bridges are the key elements in any road network. In Myanmar ridges have occupied very great importance in highway improvement ecause of the natural conditions that the topography is steep and many rivers flow. The ridge designer has choices when the waterway to e ridged is sufficiently long to require multi spans. The choice depends on many factors such as span length, foundation conditions, type of material to e used, the speed, simplicity of erection, economy, appearance, etc. A plate girder is a eam with an "H" cross section composed of steel plate elements which are connected together y welds, olts or rivets. The "H" cross section itself is comprised of two flange plates and we plate. "H" eam is developed and optimized from "I" eam, a kind of economical profiled steel with a etter mechanic capaility. It has non-tapered flanges that are wider than the standard "S" or "I" eams. Continuous ridges are typically favored when a sound foundation is availale and span lengths are greater. Compared to a simply supported structure, continuous ridges offer the advantages of reducing the numer of deck joints, earings and increasing span length. A ridge structure is divided into superstructure and sustructure. In this study, only the superstructure of ridge is considered. The superstructure is comprised of many elements such as floor slas, main girder, cross eams, sway racing. [7] To design a girder, it is necessary to known the maximum force acting at the memers due to the live load. By using computer analysis, influence lines of very complicated structure can e calculated easily. In this thesis influence lines of a three span simply supported steel girder ridge are solved y using STAAD.Pro software. II. LOAD CONSIDERATION The design of the ridge superstructure is ased on a set of loading condition which the component or element must withstand. Permanent loads are those loads which always remain and act on a ridge throughout its life. Permanent loads are divided into dead load and superimposed dead load. Temporary loads are those loads which are placed on a ridge for only a short period of time. Live load represents the major temporary loading condition. [1] A. Dead Load The dead load on a ridge superstructure consists of the weight of the superstructure plus the weight of other items. This may include the deck, wearing surface, stay-in-place forms, sidewalks and railings, parapets, primary memers, secondary memers (including all racing, connection plates, etc), stiffeners, signing and utilities. Unit weight of concrete is 150 pcf Thickness of asphalt surface is 3 in. Asphalt surface weight is 3ʺ 9 psf 7 psf. Assume size of hand rail is 6ʺ 6ʺpost 5ʹ c/c (6ʺ 4ʺ) horizontal rails. Weight of handrails is 80 l-ft. [1] B. Live Load The term live load means a load that moves along the length of a span. The moving vehicle loads that are dynamic i.e. loads change their position with respect to time. In this study, lane loading, truck loading and 014 SEMAR GROUPS TECHNICAL SOCIETY. All rights reserved.

2 ZIN MAR OO sidewalk loads are considered as love loads. The HS truck has a variale spacing etween two rear axles. This distance etween axles, varying from 14 to 30 ft is used to create a live loading situation which will induce maximum moment in a span. The highway ridges are sujected to a variety of non-stationary loads, such as those due to vehicles, motorcycles, icycles, equestrians and pedestrians. [1] Sidewalk loading applied at (600ʹ 6ʹ) area, length is 600ʹ and width is 3ʹ for oth sides. Side walk load, P W 30 (1) L psf < 60 psf For HS 0-44 truck, uniform load, ω 640 l-ft. Pressure is the ratio of uniform load per length of traffic travel. Moment for HS l Shear for HS l There are two lanes lane 1 and lane Lane load L1 for moment (midpoint) 1006 l Lane load L1 for moment (edge points) 5031 l Lane load L for shear (midpoint)14534 l Lane load L for shear (edge points)767 l C. Wind Load Like earthquake loading, wind loading offers a complicated set of loading conditions which must e idealized in order to provide a workale design. Although the prolem of modelling wind force is a dynamic one, with wind acting over a given time interval, these forces can e approximated as a static load eing uniformly distriuted over the exposed regions of a ridge. The exposed region of a ridge is taken as the aggregate surface areas of all elements as seen in elevation. The loading on a ridge due to wind forces is specified y AASHTO ased on an assumed wind velocity of 100 miles per hour. [3] D. Temperature Load Thermal forces are caused y fluctuations in temperature. The change in temperature is greatly dependent on the location of the ridge site. If one side of a structure is continually exposed to the sun while the other side is shade, the differential in temperature can cause high thermal forces. These forces generally have the most impact on earings and deck joints. A change in temperature can also affect concrete in a manner similar to shrinkage. Extreme drop in temperature can also affect steel structures. A rapid change to cold temperature can lead to a phenomenon known as rittle fracture. [1] The ranges of temperature change in this structure is considered as follow, Temperature change for axial elongation 16 F Temperature differential from top to ottom10 F Temperature differential from side to side16 F E. Seismic Load Like the vehicle live load discussed aove, seismic and wind forces are temporary load on a structure which act for a short duration. Superstructure elements are affected y seismic forces in many ways. An earthquake exerts forces on a ridge that are defined as a function of the dead weight of the structure, ground motion, period of viration and type of soil present. These factors are used to determine the response of the ridge to an assumed uniform loading on the structure. This response takes the form of an equivalent static earthquake loading which is applied to the structure to calculate forces and displacements on ridge elements. [4] Seismic zone 4 Seismic zone factor (Z) 0.4 Soil profile type S D Over strength factor, R8.5 Near source factor 1 Important factor, I1.5 F. Impact Load In order to account for the dynamic effects of the sudden loading of a vehicle onto a structure, an impact factor is used as multiplier for certain structural elements. [] I is calculated y the formula, 50 I L 5 () < 0.3 Use I III. DESIGN SPECIFICATION A. Design Data of Proposed Bridge The design of a highway ridge like most any other civil engineering project is dependent on certain standards and criteria. The AASHTO standard specifications have een accepted y many countries as the general code y which ridges should e designed. In this study, the memer will e designed according to the requirement of standard specification for highway ridge adopted y AASHTO. The design data of the proposed ridge are shown in Tale I. TABLE I: DESIGN DATA OF PROPOSED BRIDGE Type Deck Type Continuous Plate Girder Cross Section With 3 ft Sidewalk for oth sides Live Load HS 0-44 (AASHTO) Span Road Width Total Length of Bridge Continuous Span 4 ft 600 ft (end spans 150 ft, centrals span 300 ft)

3 Study on Continuous Plate Girder Highway Bridge with Dynamic Approach Wearing Surface Sla Plate girder, Cross eam and Bracing RC Sla Concrete 3 in thick Asphalt concrete 7 in thick RC concrete f y 50 ksi, f u 65 ksi Grade 40, f y 40ksi, f s 0 ksi f cʹ 4000 psi B. Model of Proposed Bridge This ridge is modelled y using STAAD-Pro software. Floor plan and 3 D model of proposed ridge is shown in Figure 1 and Figure. Figure 1. 3D View of proposed ridge. C. Load Comination for Proposed Bridge According AASHTO, Load Comination for design of the proposed ridge structure is as follows; 1. Seismic X. Seismic Z 3. Wind Load 4. Dead Load 5. Superimposed Dead Load 6. Sidewalk Live Load 7. Without Traffic Load 8. Lane 1 9. Lane 10. Lane Temperature Load. Truck Truck DL + LL 15. DL +W 16. DL + LL + W 17. DL + LL + T 18. DL + W + T 19. DL + LL + W + T 0. DL + EQX 1. DL + EQZ Where, D Dead load L Live load T Temperature load W Wind load EQX Seismic X EQZ Seismic Z Total 599 load cominations are applied on the ridge structure. The loads applied on the proposed ridge are shown in Figure 3. to 9. Figure. Floor plan of proposed ridge. Figure 3. Dead load on proposed ridge.

4 ZIN MAR OO Figure 4. Live load on proposed ridge. Figure 7. Lane- load on proposed ridge. Figure 5. Temperature load on proposed ridge. Figure 8. Traffic load on proposed ridge. Figure 6. Lane-1 load on proposed ridge. Figure 9. Moving traffic load on proposed ridge.

5 Study on Continuous Plate Girder Highway Bridge with Dynamic Approach IV. ANALYSIS AND DESIGN OF STEEL SUPERSTRUCTURE Steel ridges are widely used on highway and railway ridges. They are low weight of components, easy farication, simple installation and duraility. Steel has the advantages of lighter weight and more rapid in construction, when compared with concrete separately. [6] In this study 600 ft steel plate girder ridge superstructure is analyzed and designed with STAAD Pro software. A. Analysis Results The proposed ridge model is analyzed with the help of STAAD Pro software. Three groups of steel structural memer are included in the proposed ridge. The analysis and design procedures are in repetition process to reach the final acceptale results. From the analysis results, the maximum axial force, maximum shear force and maximum ending moment for three groups of memer are shown in Tale II. TABLE II: MAXIMUM FORCE BY SECTION PROPERTY Section W14 61 (Floor Beam) Max Axial Force (kip) Max Shear Force (kip) Bending Moment (kipin) Allowale Deflection, all x in From the output results, Maximum deflection due to live load 0.16ʺ<4.5ʺ L OK C. Design Check for Memers Sections of steel memers are designed with W-shape properties. We plate elements are checked for minimum we thickness and checked for allowale shear stress. Flange plate elements are checked for minimum flange thickness and checked for ending. The section dimensions of the memers are shown in Tale III. TABLE III: DIMENSION OF MEMBERS Memer Material Section Dimension (in) Floor Beam W Cross Beam W Bracing W W14 34 (Cross Beam) W 65 (Bracing) By using analysis results, design of floor eam, cross eam and racing are calculated y hand calculation. D. Design Check for Floor Beam The cross section of the floor eam is as shown in Figure 10. B. Check for Deflection Deflection is check caused y dead load and live load plus impact on a memer to ensure that falls elow a certain maximum value. Main span length 300 ft For Dead Load, Allowale Deflection, all x in From the output results, Maximum deflection due to dead load 0.088ʺ<10ʺ OK For Live Load, L Figure 10. Cross section of the floor eam. Maximum moment, M kip-in Maximum shear, V kip The minimum thickness of the we, for A 57 Grade 50 steel, without longitudinal stiffener can e calculated. D t min 140

6 ZIN MAR OO < t w OK Check the we for shear, V f v Dt w x ksi The allowale stress for shear in girder we for A 57 Grade 50 steel is Check for the comined stress, f f v 1. F F v OK E. Design Check for Cross Beam The cross section of the cross eam is as shown in Figure 11. F v F y ksi f v < F v OK The minimum flange plate thickness, t min ʺ< t f 0.645ʺ OK To determine the ending stress, the area moment of inertia for the main girder floor eam is calculated. t I w h 3 w x in 4 3 f t f f t f y x x 0.645x6.98 Check for ending, My f I x ksi The allowale stress for ending, F 0.55 F y ksi f < F OK Figure 11. Cross section of the cross eam. Maximum moment, M kip-in Maximum shear, V kip The minimum thickness of the we, for A 57 Grade 50 steel, without longitudinal stiffener can e calculated. D t min 140 Check the we for shear, V f v Dt w x ksi < t w 1.54 OK The allowale stress for shear in girder we for A 57 Grade 50 steel is F v F y ksi f v < F v OK The minimum flange plate thickness, t min 0

7 Study on Continuous Plate Girder Highway Bridge with Dynamic Approach in < t f.47 in OK To determine the ending stress, the area moment of inertia for the cross eam is calculated. t I w h 3 3 w + f t f t y f f (3) x x.47x x in 4 Check for ending, My f I x ksi The allowale stress for ending, F 0.55 F y ksi f < F OK Check for the comined stress, f f v F F 1. v OK F. Design Check for Bracing The cross section of the racing is as shown in Figure. Figure. Cross section of the racing. Maximum moment, M kip-in Maximum shear, V 7.1 kip The minimum thickness of the we, for A 57 Grade 50 steel, without longitudinal stiffener can e calculated. D t min < t w 0.39 OK Check the we for shear, V f v Dt w 7.1. x ksi The allowale stress for shear in girder we for A 57 Grade 50 steel is F v F y ksi f v < F v OK The minimum flange plate thickness, t min in < t f in OK To determine the ending stress, the area moment of inertia for the racing is calculated. I t wh 3 w x in f t f Check for ending, My f I x ksi The allowale stress for ending, f t f y 3 x0.605 x0.605x 6.06 (4)

8 ZIN MAR OO F 0.55 F y ksi f < F OK Check for the comined stress, f f v F F 1. v OK G. Design of Floor Sla As shown in fig 13 Sla thickness to e 7 inches for proposed design and wearing surface to e 3 inches. The spacing etween two main girders is feet and W is used in design. The effective span length of sla, S Distance etween +1/ Top Flange Width Flanges ft f c 1,600psi, r.5 K , j d 5.83 in d actual 7ʺ-1.5ʺ 5.5ʺ > 5.83ʺ OK in The required main reinforcement is, A s ft Use # 7 ar at 7 in c/c spacing (Top and Bottom) The required distriution steel is, D % < 67 % Use 67 % Distriution steel in /ft Use # 5 ar at 5.5 in c/c spacing (Top and Bottom) V. CONCLUSION In this study, the type of continuous plate girder ridge has een studied y the use of AASHTO specification. Bridge is designed under a set of moving loads. The lateral ground motion of earthquake is also considered from UBC- 97 code. To get the maximum forces in each memer, various types of loads conditions are considered. In this study, 599 numers of load cominations are considered in whole structure.. The design calculation of floor sla is 7 in thick and structural steel memers are manually calculated. Maximum deflection due to dead load is in which is less than the allowale deflection 10 in. For live load, the allowale deflection 4.5 in is greater than maximum deflection due to live load 0.16in. Also the structural steel memers are checked in shear, ending and deflection. A. Output Results Beam no Axial Force(kip) VI. APPENDIX A Shear Force (kip) Bending Moment (kipin) Figure 13. Detail cross- section of RC deck sla. A thicker sla has enhanced the overall performance of concrete decks. Decks with a wearing surface range upward from 7.5 inches. Dead load includes sla and wearing surface, so that the total dead load on the sla is DL l/ft M DL ft-l M LL ft-l M LL+I ft-l M ft-l E s 9,000,000, E c 3,604, psi n , f s 0,000psi

9 Study on Continuous Plate Girder Highway Bridge with Dynamic Approach

10 ZIN MAR OO

11 Study on Continuous Plate Girder Highway Bridge with Dynamic Approach

12 ZIN MAR OO

13 Study on Continuous Plate Girder Highway Bridge with Dynamic Approach

14 ZIN MAR OO

15 Study on Continuous Plate Girder Highway Bridge with Dynamic Approach

16 ZIN MAR OO Associate Professor and Head, Department of Civil Engineering, Mandalay Technological University for his helpful and instruction, and kindly permission and powerful encouragement. First of all, the author likes to express her thanks to her supervisor Dr. San Yu Khaing, Associate Professor, Department of Civil Engineering, Mandalay Technological University, for her close supervision, invaluale suggestion, guidance and necessary advice. The author especially thanks to all the teachers from Department of Civil Engineering, Mandalay technological University, for their effective guidance and helpful suggestion. Finally, the author would like to express grateful thanks to her teachers for their experiences and essential suggestion for this paper and all who helped directly and indirectly towards the successful completion of this study. VIII. REFERENCES [1] American Association of State Highway and Transportation Official: AASHTO LRFD Bridge Design Specifications, Sixteenth Edition with Permission, (1998). [] Charles G. Salmon and John E. Johnson. Steel Structure: Design and Behavior. 3 rd Edition. New York: Haper Collins Pulishers, [3] ASCE, American Society of Civil Engineers, Design Loads for Buildings and other Structures: Revision of ASCE7-98, ASCE Pulication, Virginia, U.S.A, 003. [4] Uniform Building Code, Volume. Structural Engineering Design Provision, 8 th Edition, International Conference of Building Officials, [5] Alfred Hedefine.NY, John Swindlehurst. N.J and Mahir Sen.N.J: Beam and Girder. [6] McGraw- Hill, INC: Structural Steel Designer s Handook. 3 rd Edition. [7] Michael Baker Jr Inc: LRFD Design Example for Steel Girder Superstructure Bridge, VII. ACKNOWLEDGMENT The author would like to acknowledge the support and the encouragement of Prof. Dr. Myint Thein, Pro-rector, Mandalay Technological University. The author heartily to express his deeply gratitude to Dr. Kyaw Moe Aung,