- Page 1 Problem Statement A Highway Bridge Is To Be Designed Across A Canal Having The Following Section View The Widt 1 (59.34 KiB) Viewed 15 times
Page: 2 Truss Geometry and loads pent 12.75ft Top chords AISC shape = L6X6X9/16 Bottom Chords AISC shape W14X90 Web members AISC shape = WT9X87.5 fort 20 32.5kips 3.1875ft 6.375ft D 32.5kips 65kips 65kips 65kips 76.5ft Tasks: Problem 1a -Stiffness Method Total = 50 • Draw the truss. Put node numbers, member numbers and degrees of freedom numbers [Marks: 10] • Calculate all member stiffness matrices in the global coordinate system and assemble them in a structure stiffness matrix, i.e. k matrix. [Marks:20] • Write the stiffness equation, solve for unknown displacements and calculate unknown forces by matrix operations. You may use Microsoft excel for calculations but you have to submit handwritten papers. [Marks: 20] • All calculations must be shown in handwriting, no printouts are allowed.
Page: 3 Tasks: Problem 1b - Force Method Marks:= 30 • Perform a complete analysis of the truss by the force method • All required analyses may be done by using application software (STAAD/ETABS) but those files are not required in the submission. Present only the member forces on the truss. • Calculations may be done in Microsoft excel worksheets. Printouts are allowed. Option 2: Reinforced concrete deck-girder bridge. Six girders are to be placed underneath the bridge deck. An intermediate support as a portal frame is required for deflection and vibration control. The left support will be fixed to the abutment while the intermediate and the right supports are roller. Two problems: Problem 2a with Marks 50 and Problem 2b with Marks 30= Total Marks 80 A typical concrete girder CHARENTE ●● Side view of the intermediate support as a portal frame
Page: 4 23.25kip/ft Ga 33inch x 29inch Girder 63ft 63ft 13.3ft 8.1375kip/ft 19inch x 29inch 19inch x 33inch 33inch x 33 inch Columns Problem 2b. Intermediate support Portal frame Problem 2a. Concrete girder P = 19 kips Tasks: Problem 2a - Stiffness Method Total marks = 50 • Draw the beam. Put node numbers, member numbers and degrees of freedom numbers [Marks: 10] • Calculate member stiffness matrices in the global coordinate system and assemble them in a structure stiffness matrix, i.e. k matrix. [Marks: 10] • Write the stiffness equation, solve for unknown displacements and calculate unknown forces by matrix operations. You may use Microsoft excel for calculations but you have to submit handwritten papers. [Marks: 10] • Calculate reactions. Draw the Shear force diagram and the bending moment diagrams [Marks: 10] • Based on the Bending moment diagram determined above, justify the choice of having the girder as h₂ inch x h, inch. Find a suitable AISC W shape for fy= 36 ksi. [Marks: 10]
Page: 5 Tasks: Problem 2b - Moment Distribution Method Total = marks 30 • Calculate stiffness of all members and determine distribution factors for all joints. Calculate Fixed End Moments. [Marks: 10] • Perform a moment distribution for determination of moments at the ends of all members. [Marks: 10] • Calculate final reactions at all supports. Draw the shear force and the bending moment diagrams for the frame. [Marks: 10] • Comment on the suitability of the chosen concrete cross-section dimensions (50 - 100 words)