MODELLING AND ANALYSIS OF FLYOVER DECK SLAB WITH U-BOOT TECHNOLOGY

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1 International Journal of Civil Engineering and Technology (IJCIET) Volume 9, Issue 8, August 2018, pp , Article ID: IJCIET_09_08_039 Available online at ISSN Print: and ISSN Online: IAEME Publication Scopus Indexed MODELLING AND ANALYSIS OF FLYOVER DECK SLAB WITH U-BOOT TECHNOLOGY Dr. H. Sudarsana Rao Director of Academic Audit, JNT University, Ananthapur, AP, India M. Surya Prasanth P.G. Student, Computer Aided Structural Engineering, JNT University, Ananthapur, AP, India ABSTRACT In present days, enhancing of population taking place day by day and due to excess population, enhancing of traffic is also taking place. Due to heavy traffic, accidents are also increasing because of congestion of roads. To reduce the congestion on roads, the pavements provided to be widened and hence the number of lanes must be increased. But due to minimum budget, contractors are building limited number of lanes which causes accidents. This paper presents a new methodology to increase the number of lanes without exceeding the cost. This can work out with U- Boot technology. It is the technique applied where U-Boots can be placed in deck slab along with concrete and steel with proper arrangement. As U-Boot is a plastic product, it minimizes the self weight of deck slab and also reduces the depth of slab with same strength. It also reduces the amount of concrete and steel provided on deck slab. The quantity of concrete and steel saved by placing U-Boots can be used for constructing other lanes. For modeling NX-CAD software is used and for analysis NX-NASTRAN is used. The details of modeling and analysis are presented in this paper. Key words: U-BOOT, NX-CAD, NX-NASTRAN, Deck Slab and Flyover. Cite this Article: Dr. H. Sudarsana Rao and M. Surya Prasanth, Modelling and Analysis of Flyover Deck Slab with U-Boot Technology. International Journal of Civil Engineering and Technology, 9(8), 2018, pp INTRODUCTION The U-Boot gives a creative response for laying of slabs with mushroom columns with the extraordinary characteristics of the mushroom being a part of thickness of slab. This new lighter structure is achieved by encasing the U-Boot inside the solid cast. The lighter structure is comprised of two level layers one over the other separated and associated with each other by beams at right angles. The laying of U-Boots in the deck slab is shown in Fig editor@iaeme.com

2 Dr. H. Sudarsana Rao and M. Surya Prasanth Figure 1 laying of U-Boots in Deck Slab As per the data provided by the U-Boot Beton Company, the reduction in the quantity of material reduced with U-Boot is presented in Table 1. Table 1 Reduction of material savings with u-boot Type of Structure Material Concrete Steel Slab -15% -25% Pillars -20% -35% Foundation -20% -35% 1.1. Spacer Joint Spacer joint is the important component in U-Boot technology. The U-Boots provided in perpendicular directions may not be seated rigidly and hence it has a chance of having disturbances in U-Boots. To avoid these disturbances, the U-Boots must connect to each other with spacer joint. So when concrete is poured the U-Boots will not get disturbed. The spacer joint is fitted on top of U-Boot shown in Fig 2 highlighted with red colour. Figure 2 Spacer Joint editor@iaeme.com

3 Modelling and Analysis of Flyover Deck Slab with U-Boot Technology 2. LITERATURE REVIEW [1] Northam R. (2009) In this paper, the slabs are made with plastic ball to reduce the self weight of the structure. The main aim of this paper is to give a report about punching shear on voided slabs with plastic balls. Since the punching shear limit is the most important property of flat slab, this paper studies about the punching shear on plastic balls. This paper used steel fibers with 0.8% and 1% for defining punching load and deflection. This paper concludes for voided slab, the punching strength with steel fiber 0.8% and 1% is increased by 2.56% and 7.7% respectively on comparison with voided slab without steel fiber. Also the deflection increased by 3.153% and % respectively. [2] Lai T. (2009) In bubble deck system, the concrete at the center of deck is removed and hence the slab becomes very light on comparison with solid slabs. In reinforced concrete structures, the ductility factor is important. It contains the shear walls and the flat slabs having plastic bubbles inside the system. This paper studies, the fluctuations of the ductility in case of reinforced concrete structures constructed with bubble deck are evaluated by doing nonlinear static analysis. Based on the results, it is concluded that the ductility is more for dual systems on comparing with single moment resisting system. Ductility factor will decrease by increasing the ratio of the length of span to storey height (L/H). Low-rise structures with high (L/H) have the least value of ductility. [3] Abramski M., Albert A., Pfeffer K., Schnell J. (2010) The main aim of this paper is to give a report about shear force on flat slabs with circular voids by varying percentage of steel. This paper used two different percentages of steel i.e. 0.31% and 0.52%.The investigation was made using Atena 3-D finite element software. It compares the results of these model values with experimental values. It shows flat slabs with circular voids reduce the shear force on comparison with solid slab. All models with voids that have the reinforcement ratio of 0.52% failed in shear and those with ratio of 0.31% failed in bending. [4] U-Boot Beton technical data by daliform group The technical data regarding U-Boot i.e. size of U-Boot, height of U-Boot, foot height of U- Boot, material saving with U-Boot, installation procedure, applications are provided. In this paper, single U-Boot is used with size 52 x 52 cm, height of U-Boot is 28.8 cm and foot height is 5 cm. [5] Saifee Bhagat, Dr. K. B. Parikh (2014) In this paper, the stiffness factor, percentage of weight saving is calculated for different ball diameters i.e. 180, 225, 270, 315, 360, 405, 450 mm. On comparing the results, the stiffness reduction factor is more for ball diameter 180 mm i.e And less for ball diameter 405 mm i.e the percentage of weight saving for ball diameters 180, 225, 270, 315, 360, 405, 450 mm are 20.62, 26.77, 28.98, 30.07, 32.48, 33.03, respectively. On comparing more weight is saved with ball diameter 405 mm. [6] Arati Shetkarand & Nagesh Hanche (2015) In this paper, an experimental study is carried out on bubble deck slab made with elliptical balls made of polypropylene. This paper gives a report regarding deflections for two different grades of concrete i.e. M25 and M35 and with different diameters of elliptical balls i.e. 180, editor@iaeme.com

4 Dr. H. Sudarsana Rao and M. Surya Prasanth 186 and 240 mm. All the five specimens are made with same dimensions. On comparing the five specimens, the specimen with M35 grade of concrete with diameter 186 mm shows less deflection with value mm. [7] Subramanian K and Bhuvaneshwari P (2015) In this paper, Finite element analysis is performed using ANSYS software on six specimens in which 3 are solid slabs and others are voided slabs. The slab specimens made with dimensions mm are tested with symmetric boundary conditions. The void diameter is taken as 70 mm with a wall thickness of 1 mm and is assumed to be made up of HDPP. The clear spacing between the voids varied between 30, 50 and 70 mm. The voids with a spacing of 30 mm prove to be more efficient because even though removes 20% of concrete, the deflection shown by the specimen is near to that of solid slabs. The results from finite element analysis are compared with that of plate theory which is used to compute reference values of deflection for corresponding load. The maximum deflection observed for V30 slab was mm by numerical methods. [8] Harishma K.R and Reshmi K N (2015) In this paper, an experimental study is carried out on bubble deck slab made with elliptical balls made of polyethylene. This paper gives a report regarding deflections for four different types of slabs i.e. conventional slab, continuous slab, alternative slab with zigzag arrangement and alternative slab with regular arrangement. On comparing 4 types of slabs the load carrying capacity is more for continuous slab i.e. 320 KN. The load carrying capacity for conventional slab, alternative slab with zigzag arrangement and alternative slab with regular arrangement are 260, 290 and 275 KN respectively. The deflections occurred for conventional slab, continuous slab, alternative slab with zigzag arrangement and alternative slab with regular arrangement are 8.7, 9.2, 8.95 and 8.8 mm respectively. On comparison the deflection is more for continuous slab. 3. INSTALLATION The following are the steps to be followed when installing U-Boots. 1. Initially the reinforcement bars are provided at the bottom in two perpendicular directions. 2. After placing the bottom reinforcement, u-boots are placed in both directions. 3. The U-Boots must be joined with spacer joint to counteract the lateral movements. 4. After placing uboots, the top reinforcement bars are provided in two directions. 5. After placing the top bars, concrete should be poured on the top to fill the gaps between the U-Boots and reinforcement. 6. Once the structure has hardened, the formwork can be evacuated. The final view of U-Boot installation is depicted in Fig 3. Figure 3 Installation of U-Boots editor@iaeme.com

5 Modelling and Analysis of Flyover Deck Slab with U-Boot Technology 4. MODELLING OF FLYOVER For modeling of flyover the following components are assembled. 1. Pile 2. Pile cap 3. Pier 4. Pier cap 5. Bed Block 6. Rocker and Pin Bearing 7. Deck Slab with U-Boot This Project compares two types of flyover i.e.., Flyover deck slab With U-Boot and Flyover deck slab without U-Boot. The details of which is presented below Flyover deck slab With U-Boot In case of flyover deck slab with U-Boot, it is not required to provide beams shown in Fig 4. Hence it is possible to provide lighter slab with reduced self weight. It also improves the appearance. Figure 4 Flyover without beams 4.2. Flyover deck slab Without U-Boot In case of flyover deck slab without U-Boot, it is required to provide beams which increase the cost of structure shown in Fig 5. It also looses the appearance. Figure 5 Flyover with beams editor@iaeme.com

6 Dr. H. Sudarsana Rao and M. Surya Prasanth 5. RESULTS AND DISCUSSIONS 5.1. Results of Flyover Deck Slab with U-Boot by NX-Nastran After analyzing the model of flyover deck slab with U-Boot by NX-Nastran, the following results are obtained with maximum and minimum values. The maximum principal stress with U-Boot in deck slab by NX-Nastran is shown in Fig 6. Figure 6 Maximum Principal Stress with U-Boot The maximum shear stress with U-Boot in deck slab by NX-Nastran is shown in Fig 7. Figure 7 Maximum Shear Stress with U-Boot The displacements with U-Boot in deck slab by NX-Nastran are shown in Fig 8. Figure 8 Displacements with U-Boot editor@iaeme.com

7 Modelling and Analysis of Flyover Deck Slab with U-Boot Technology The maximum and minimum Values for different parameters under 100 KN Load on Deck Slab with U-Boot is shown in Table 2. Table 2 NX-Nastran Values for different parameters under 100 KN Load on Deck Slab with U-Boot Parameters Minimum Value Maximum Value Displacement Nodal (mm) X Y Z Magnitude Stress Elemental (Mpa) XX YY ZZ XY YZ ZX Determinant Mean Maximum Shear Minimum Principal Mid Principal Maximum Principal Worst Principal Octahedral Vonmises Stress Elemental Nodal (Mpa) XX YY ZZ XY YZ ZX Determinant Mean Maximum Shear Minimum Principal Mid Principal Maximum Principal Worst Principal Octahedral Vonmises Reaction Force (N) X Y Z Magnitude editor@iaeme.com

8 Dr. H. Sudarsana Rao and M. Surya Prasanth 5.2. Results of Flyover Deck Slab without U-Boot by Nx-Nastran After analyzing the model of flyover deck slab without U-Boot by NX-Nastran, the following results are obtained with maximum and minimum values. The displacements without U-Boot in deck slab by NX-Nastran are shown in Fig 9. Figure 9 Displacements without U-Boot The maximum principal stress without U-Boot in deck slab by NX-Nastran is shown in Fig 10. Figure 10 Maximum Principal Stress without U-Boot The maximum shear stress without U-Boot in deck slab by NX-Nastran is shown in Fig 11. Figure 11 Maximum Shear Stress without U-Boot editor@iaeme.com

9 Modelling and Analysis of Flyover Deck Slab with U-Boot Technology The maximum and minimum Values for different parameters under 100 KN Load on Deck Slab without U-Boot is shown in Table 3. Table 3 NX-Nastran Values for different parameters under 100KN Load on Deck Slab without U-Boot Parameters Minimum Value Maximum Value Displacement Nodal (mm) X Y Z Magnitude Stress Elemental (Mpa) XX YY ZZ XY YZ ZX Determinant Mean Maximum Shear Minimum Principal Mid Principal Maximum Principal Worst Principal Octahedral Vonmises Stress Elemental Nodal (MPa) XX Yy ZZ XY YZ ZX Determinant Mean Maximum Shear Minimum Principal Mid Principal Maximum Principal Worst Principal Octahedral Vonmises Reaction Force (N) X Y Z Magnitude Discussion of Results Fig 8 and Fig 9 shows the displacements of deck slab with and without U-Boot respectively. On comparing the results of deck slab with and without U-Boot by NX-Nastran, the maximum editor@iaeme.com

10 COST OF MATERIAL IN RUPEES Dr. H. Sudarsana Rao and M. Surya Prasanth and minimum deflections occurred are less with U-Boot shown in Table 1 and Table 2. The percentage of deflection reduced with U-Boot is 20%. Fig 7 and Fig 11 shows the Shear stresses of deck slab with and without U-Boot respectively. On comparing the results of deck slab with and without U-Boot by NX-Nastran, the maximum and minimum shear stresses developed are less with U-Boot shown in Table 1 and Table 2. The percentage of shear stresses reduced with U-Boot is 20.02%. Fig 6 and Fig 10 shows the principal stresses of deck slab with and without U-Boot respectively. On comparing the results of deck slab with and without U-Boot by NX-Nastran, the maximum principal stresses occurred are less with U-Boot shown in Table 1 and Table 2. The percentage of principal stresses reduced with U-Boot is 3.14% Cost Analysis The comparison of costs of concrete and steel are shown in Fig 12 which is self explanatory. 600 COST ANALYSIS OF DECK SLAB ( ) WITH U-BOOT WITHOUT U-BOOT CONCRETE STEEL Figure 12 Comparison of costs of concrete and steel 6. CONCLUSIONS By using U-BOOT Technology, it is possible to save large amount of concrete and steel and also possible to reduce the self weight of the structure. On comparison with the deck slab without U-BOOT, it has less deflections and stresses at different nodal points shown in table1 and table 2.The cost of the deck slab construction also will be reduced with U-BOOT technology. As stresses developed are less, the load carrying capacity of deck slab also can be increased. REFERENCES [1] Northam R. Biaxial Flat Slab Floor Construction concrete frame construction, February 2009, p [2] Lai T. Structural Behavior Of Bubble deck Slabs And Their Application To Lightweight Bridge Decks. Msc thesis in civil engineering, Massachusetts Institute of Technology,2009 [3] Abramski M., Albert A., Pfeffer K., Schnell J. Experimental and Numerical Investigations of the Load-Bearing Behaviour of Reinforced Concrete Slabs Using Spherical Void Formers, Beton- und Stahlbetonbau 105 (2010), No editor@iaeme.com

11 Modelling and Analysis of Flyover Deck Slab with U-Boot Technology [4] U-Boot Beton technical data by daliform group [5] Saifee Bhagat, Dr. K. B. Parikh Comparative Study of Voided Flat Plate Slab and Solid Flat Plate Slab, ISSN , Vol. 3 Issue 3, March, [6] Arati Shetkarand & Nagesh Hanche an Experimental Study On bubble deck slab system with elliptical balls, NCRIET-2015 &Indian J.Sci.Res. 12(1): , [7] Subramanian K and Bhuvaneshwari P Finite Element Analysis of Voided Slab with High Density Polypropylene Void Formers International Journal of Chem Tech Research, CODEN (USA): IJCRGG ISSN: , Vol.8, No.2, pp , 2015 [8] Harishma K.R and Reshmi K N A study on Bubble Deck slab, International Journal of Advanced Research Trends in Engineering and Technology (IJARTET) Vol. II, Special Issue X, March editor@iaeme.com