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Experimental study of precast portal frame

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Growing of Precast construction system has given emphasis on improving work zone safety, reducing construction time and environmental impact, while maintaining the quality. The connections are the most important part of precast construction systems, being the general behavior of the precast structures related to their design, construction and performance. In this civil engineering project a trial to compare the strength of three types of portal frames viz. Monolithic Portal Frame, Portal Frame with corbel and Portal Frame without corbel and their deflections at various loads were observed and derived conclusion which one is efficient among all frames designed and cast.

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Experimental study of precast portal frame

  1. 1. EXPERIMENTAL STUDY OF PRECAST PORTAL FRAME 2CL404 – CIVIL ENGINEERING PROJECT ee Presented By:- SAGAR HALWAWALA (11BCL014) HIMANSHU MANOLKAR (11BCL015) SATISH KAMBALIYA (11BCL016) MEET KOTADIA (11BCL020) Guided By:- Dr. P.V. Patel
  2. 2. Introduction • Precast concrete :- Construction product produced by casting concrete in a reusable mould or "form" which is then cured in a controlled environment, transported to the construction site and lifted into place. • Increasingly popular in the construction industry.• Increasingly popular in the construction industry. • Also referred to as Modern Methods of Construction (MMC). • Extensively used for a wide variety of projects, from railway sleepers to bridge elements, housing and stadia. • Reduction in waste on construction site by as much as 50% when compared to more traditional approaches.
  3. 3. Introduction cont... • It is due among other factors to the advantages related to the reduction in construction times, work force and in situ labors, as well as a more favorable cost-benefit relation, less environmental impacts, and greater control and final quality of the elements. • Utilizing a Precast Concrete system offers many potential• Utilizing a Precast Concrete system offers many potential advantages over site casting of concrete. The production process for Precast Concrete is performed on ground level, which helps with safety throughout a project. • There is a greater control of the quality of materials and workmanship in a precast plant rather than on a construction site.
  4. 4. Types of Precast System. Depending on the load bearing structure, precast systems can be divided into the following categories: Large-panel systems Frame systems Slab-column systems with walls Mixed systems Volumetric construction
  5. 5. Precast Components
  6. 6. Precast Building In India Pragati Tower is a G+23 storeys fully precast residential building project with 6 towers at6 towers at Bhoiwada, Parel, Mumbai, India to rehabilitate slum dwellers.
  7. 7. Need Of Precast Construction • Precast concrete solutions can provide construction elements that are made of recycled materials that generate small amounts of waste through the manufacturing and erection phases. These precast products are widely used in the following sectors: Residential (floors) StadiaStadia Infrastructure (roads, railways, bridges, sewage) Prisons Medium and high rise building Hospitals Commercial and industrial buildings
  8. 8. Need Of Precast Construction cont. • Their utilization saved construction time and cost, insured better quality control, and suggested the achievement of standardization. • Its fulfills criteria of three “R” of Sustainable Development ie.Development ie. Reduce Recycle Reuse
  9. 9. Advantage Of Precast Construction • Quick erection times. • Reduced need for plant on site. • Easier management of construction sites. • Better overall construction quality.• Better overall construction quality. • Ideal fit for simple and complex structures. • The forms used in a precast plant may be reused hundreds to thousands of times before they have to be replaced, which allow cost of formwork per unit to be lower than for site-cast production.
  10. 10. Limitations • High Initial cost. • Lack of local availability of elements. • Transportation • Erection• Erection
  11. 11. Objective Of Project The key objectives of study are as follows. • To study the basics of precast joints. • To study the behaviour of joints in precast concrete• To study the behaviour of joints in precast concrete portal frame by experimental study. • To compare experimental results of monolithic specimen and precast specimens (with and without corbel) and derive conclusion which is comparatively efficient.
  12. 12. Scope Of Study • Analysis and design of the Portal Frames. • Taking a building with continuous slab and designing intermediate portal frame from it.
  13. 13. Scope Of Study • Designing of a monolithic portal frame and two precast portal frame one with corbel and one without corbel. • Casting of the scaled down specimen of each• Casting of the scaled down specimen of each type of the portal frame. • Testing the portal frame as per experimental setup. • Based upon experimental data, comparing portal frames and deriving out conclusion.
  14. 14. DESIGN OF PORTAL FRAMESDESIGN OF PORTAL FRAMES
  15. 15. MIX DESIGN • Design Data 1. Characteristic strength required at 28 days = 25 MPa 2. Maximum size of aggregate = 10 mm2. Maximum size of aggregate = 10 mm 3. Degree of workability = medium 4. Degree of quality control = fair 5. Type of exposure = Moderate
  16. 16. • Test data of materials:- 1. Compressive strength of OPC cement 53 N/mm2 2. Specific gravity of cement = 3.152. Specific gravity of cement = 3.15 3. Specific gravity of coarse aggregate = 2.78 4. Specific gravity of fine aggregate = 2.54
  17. 17. Final Mix Design Concrete Grade Cement OPC 53 W/C Coarse Aggregate Fine Aggregate grade M-25 1 0.54 2.51 1.96 M-25 390 kg 210.6 978.84 kg 762.61 kg
  18. 18. Design Consideration • Three test specimens of one forth scale model were cast and tested under two point load. The design and detailing of portal frame had been done based on the guidelines given in IS: 456-2000, IS: 13920. • Dimension of actual portal frame of :-• Dimension of actual portal frame of :- 1. Span – 8m 2. Height – 4m 3. Cross section of beam- 400x600 4. Cross section of column – 400x800
  19. 19. Designed Portal Frame
  20. 20. Dimensional Analysis and Scaling Of Portal Frame • As large specimens were difficult to handle so casting of scaled down specimen for study. • Therefore using Buckhimgam Pie theorem and taking a reduction factor of 1:4 calculation were made and following model was decided for experimental testing. 1. Span – 2m 2. Height – 1m 3. Cross section of beam- 100x150 4. Cross section of column – 100x200
  21. 21. Scaled Down Portal Frame
  22. 22. Reinforcement Detailing Of Monolithic Portal Frame
  23. 23. Precast Portal Frame 1).Without Corbel • This frame design consists of a L shaped column spanning 300 mm out of column with 150mm bars projecting out, accompanied150mm bars projecting out, accompanied with 900mm beam casted separately with 150mm bars projecting out, welding of 110mm on either side of the beam with a gap of 150mm in between the beam approaching beam from column side.
  24. 24. 1). Detailing Of Portal Frame Without Corbel
  25. 25. 2). With Corbel • In this frame corbel of 110 mm long and 200mm depth were designed having two dowel bars in corbel and two M10 bolts were used. • Beam 1770mm long having hole for bolts were designed and welding of 110 mm of columns bar and beam bar were done. • 15mm spacing were kept on both side of beam for concreting.
  26. 26. Detailing Of Portal Frame With Corbel
  27. 27. EXPERIMENTAL PROGRAMME OF PORTAL FRAME EXPERIMENTAL PROGRAMME OF PORTAL FRAME
  28. 28. Steps for Experimental Analysis 1. Trial mix for the concrete mix design 2. Casting of covers (20mm) 3. Setting up of form work 4. Tie up the reinforcement cage4. Tie up the reinforcement cage 5. Connection of column and base plate by welding 6. Placement of the reinforcement cage into the formwork 7. Casting of the Portal Frame 8. Curing 9. Setting up of portal frame in test set up frame
  29. 29. Trial mix for the concrete mix design Three cubes of 150*150*150mm were150*150*150mm were casted as per obtained mix design for M25 grade of concrete and were tested for 7 days strength.
  30. 30. The cubes were tested on Universal Testing Machine after seven days and result obtained was 16.5 N/mm^2. Which is 66% of 25N/ N/mm2.66% of 25N/ N/mm .
  31. 31. Casting of covers (20mm) • Tea cups were used for casting of mortar cover having proportion of 1:2. and then binding wire were inserted in it. • Cups were kept in water and cured for three days.
  32. 32. 1).Methodology For Monolithic Portal Frame Tie up the reinforcement cagereinforcement cage of column •Column with end to end length of 1075mm and beam with end to end length of 2200 mm was casted.
  33. 33. Reinforcement cage of Beam
  34. 34. Placement of reinforcement cage into formwork
  35. 35. •8 mm thick steel plate was used to serve purpose Connection of column and base plate by welding was used to serve purpose of footing for stability of the frame. •Reinforcement bars of column at bottom was welded with plate by 120mm length.
  36. 36. • Wooden logs were firmly kept for connecting base plate to form work.
  37. 37. •Casting of frame were performed, vibrator was used for removing the voids. Cubes were arranged on sides of were to prevent expulsion of formwork and to have desired shaped frame. Casting of the Portal Frame Curing •After Casting, curing were done for 28 days and gunny bags were used for this purpose. •After 28 days of casting, the frame was arranged as per set up.
  38. 38. Setting up of frame in test set up and Measuring Verticality of frame with plumb bob.plumb bob.
  39. 39. Test Setup • Test setup consists of loading frame on which four ISMB 150 were rigidly fixed by the means of metal nuts, bolts and wires. Upon this portal frame having base plate 8mm thick is connected to the ISMB 150 by the help of clamps. Furthermore the testing assembly consists of 5 dial gaugesFurthermore the testing assembly consists of 5 dial gauges placed at 100mm, 450mm, 1000mm, 1450mm and 1900mm from the left hand side respectively. • For application of load a 250 kN hydraulic jack is mounted at the top of the loading frame facing downward side below which an ISMB 200 section was placed over two roller support 330mm from the middle of the support on either side.
  40. 40. 2).Methodology For Precast Portal Frame without Corbel •Placing Reinforcement Cage into formwork of 900 mm long. •Bars extending on both sides of 130mm long for connecting it to bars of column.
  41. 41. Different components were arranged in level to have proper connections. Reinforcing Bars extending from columns and Beams are welded of length 110mm with the help of mobile welder.
  42. 42. •Placing of form work for Micro Concreting, which were sealed with M-seal in order to prevent leakage.
  43. 43. Using Micro-concrete in proportion of 1:2 with proper stirring, and pouring Micro Concrete and curing it for 28 days.
  44. 44. Setting up the Frame in the laboratory with the help of crane which is electrically operated.
  45. 45. Grinding the surface for making it even and checking the verticality with the help of spirit level.
  46. 46. Test Setup • Two beam of ISMB 300 were kept at end and over it beam of ISMB 500 were kept and above it specimen were kept. Above specimen two rollers of 50mm were kept for providing support and above it beam ISMB 200 were kept and spacer of 100mm were used and then jack of 100kN, 300mm height were used thus completing full length of 2000mm height.were used thus completing full length of 2000mm height. • For application of load a 100kN hydraulic jack is mounted at the top of the loading frame facing downward side below which an ISMB 200 section was placed over two roller support 330mm from the middle of the support on either side.
  47. 47. 3).Methodology For Precast Portal Frame with Corbel In this frame Corbel of size 110*110*200 and two Dowel Bars of 10mmBars of 10mm diameter are designed.
  48. 48. Binding of M10 bolts with Dowel Bars
  49. 49. Placing of PVC pipes in beam for maintaining holes for bolts
  50. 50. Fixing the bolts emerging out from the column into the beam and welding the Reinforcing Bars of column and beam with the help of mobile welder, then Micro concreting is done.
  51. 51. •After casting of Pre-cast elements, Micro-concreting is done by proper stirring in proportion of 1:2. •And curing it for 28 days. •Then setting up the frame in the laboratory, and test setup islaboratory, and test setup is similar to that of frame without corbel.
  52. 52. EXPERIMENTAL RESULTS OFEXPERIMENTAL RESULTS OF PORTAL FRAMES
  53. 53. Results Of Monolithic Portal Frame 40 50 60 LOAD(kN) Load vs Deflection 900L 0 10 20 30 0 5 10 15 20 25 30 LOAD(kN) DEFLECTION(mm) 900L 450L centre 900R 450R
  54. 54. Results Portal Frame without Corbel
  55. 55. Results Portal Frame with Corbel
  56. 56. 30 40 50 60 70 80 90 LOAD(KN) LOAD VS DEFLECTION AT 100 mm FROM LEFT 0 10 20 30 -1 0 1 2 3 4 5 6 7 8 DEFLECTION(mm) Monolithic Without Corbel With Corbel
  57. 57. 40 50 60 70 80 90 LOAD(KN) LOAD VS DEFLECTION AT 550 mm FROM LEFT 0 10 20 30 0 2 4 6 8 10 12 14 16 LOAD(KN) DEFLECTION Monolithic Without Corbel With Corbel
  58. 58. 40 50 60 70 80 90 LOAD(KN) LOAD VS DEFLECTION AT 1000 mm FROM LEFT 0 10 20 30 0 5 10 15 20 25 30 LOAD(KN) DEFLECTION Monolithic Without Corbel With Corbel
  59. 59. 40 50 60 70 80 90 LOAD(KN) LOAD VS DEFLECTION AT 1450 mm FROM LEFT 0 10 20 30 0 5 10 15 20 LOAD(KN) DEFLECTION Monolithic Without Corbel With Corbel
  60. 60. 40 50 60 70 80 90 LOAD(KN) LOAD VS DEFLECTION AT 1900 mm FROM LEFT 0 10 20 30 0 2 4 6 8 10 DEFLECTION Monolithic Without Corbel With Corbel
  61. 61. Observation For Cracks Of Monolithic Portal Frame
  62. 62. Observation For Cracks Of Portal Frame without Corbel Shear crack observed at 52.5 kN. @left corner of frame
  63. 63. Tension Crack observed at 60.5 kN @ top at corner on both side
  64. 64. Crack observed between point load and centre @ 65.0 kN
  65. 65. Crack observed at 67.5 kN
  66. 66. Crack observed at connection @ 70 kN
  67. 67. Cracks Observed @ 72.5 kN
  68. 68. Major Crack observed at connection @ 80 kN at point load
  69. 69. Observation For Cracks Of Portal Frame with Corbel Shear Crack observed at 50 kNat 50 kN
  70. 70. Minor Crack Observed at point load @ 55 kN
  71. 71. Minor Crack Observed between center and point load @62.5 kN
  72. 72. Major Failure at 67.5 kN
  73. 73. Summary • In this study taking a building with continuous slab and designing intermediate portal frame from it. • Further casting and testing of one forth scaled specimen of monolithic portal frame , and twospecimen of monolithic portal frame , and two precast portal frame one with corbel and one without corbel were carried out. • Testing of the portal frames were done as per experimental setup. • Based upon experimental data, comparing portal frames and deriving out conclusion.
  74. 74. Conclusion • Deflection pattern through out the testing followed similar pattern i.e. maximum deflection is observed in case of monolithic frame, than portal frame without corbel followed by portal frame with corbel. • This shows that Monolithic Frame is more ductile than Pre-cast Frame, but carries low load.Pre-cast Frame, but carries low load. • However it is observed while testing portal frame with the corbel that deflection at center of span were similar to deflection at 450mm distance on both side of center. • However this could be attributed to presence of the corbel as due to presence of corbel proper fixity is not obtained at support and there is rotation which would results in similar kind of deflection.
  75. 75. 28.4 15 20 25 30 Deflection(kN) Maximum Deflection of Portal Frame(mm) 10.1 12.8 0 5 10 15 With Corbel Without Corbel Monolithic Deflection(kN)
  76. 76. 55 67.5 80 40 50 60 70 80 90 UltimateLoad(kN) Ultimate Load monolithic with corbel without corbel load 55 67.5 80 0 10 20 30 40 UltimateLoad(kN) Type of system
  77. 77. • Load carrying capacity of frame without corbel is 15% more than frame with corbel and 31% more than monolithic frame. • Deflection is also between monolithic and with corbel frame. • Thus portal frame without corbel is more• Thus portal frame without corbel is more efficient comparatively. • After going through study it can be well concluded that the precast construction can perform well unconventional to that of the existing belief.
  78. 78. Thank YouThank YouThank YouThank YouThank YouThank YouThank YouThank You

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