Requirement:
1) Finish the following question and submit your assignment through Dropbox;
2) Provide detailed solving process;
3) Either print or handwriting will be fine, but the handwriting must be neat and clear;
4) Assignments with the same wrong results and the same process will be treated as a group work, and the score will be shared by the participants.
Problem - Girder Design
A welded two span girder beam is required for a heavy industry application shown in Figure
1. The beam supports temporary loads on each of the two spans as shown in Figure 2. There are three load cases should be considered. Load case a represent load P1 only whereas load case b represents load P2 only. The load case c is the combination of a and b.
Assume that a live load factor of 1.5 is applicable.
Figures 3 shows the physical connection of Support A. Assume that the Supports C and E are laterally restrained and restrained against twisting. There is lateral restraint to the top flange only at the two load point locations (Point B and D in Figure 2). The stiff support bearing length at point C and E are both 100mm long.
Assume the flange, web and any stiffener material all have a yield strength fy = 320MPa and the beam is heavily welded i.e. HW class.
Part 1
The moment and shear force diagrams are supplied for load cases a and b are shown in Figure 4.
Using moment distribution method, derive the bending moment and shear force diagram for load case a and check against the given diagram in Figure 4.
Part 2
Verify that the section shown in Figure 1 has the following section properties.
Ix = 15,720.0 x106 mm4, Iy = 256.1x106 mm4, Iw = 165.5x1012 mm6,
Zx = 19,270.0 x 103 mm3, Sx=21,710.0x103 mm3, J = 4.222x 106 mm4
If you are not able to verify these values, you may adopt the above section properties to answer the remaining assignment questions.
Part 3
Verify that the effective section, Ze is 12,366 x 103 mm3 (approx.).
If you are not able to verify this value, you may adopt this effective section property to answer the remaining assignment questions.
Part 4
Divide the member in segments as applicable and check that the member capacity is greater than the maximum moment M* for that segment.
Method - As a guide for you, set out your workings in the following order:
1. Consider all the segment of the top flanges first, then segment of the bottom flanges when calculating segment capacities.
2. For each segment
a. Clearly indicate assumed segment end conditions
b. Calculate the effective length
c. Calculate the slenderness reduction factor αs
d. Calculate moment modification factor calculation αm
e. Determine the member capacity
Part 5
Calculate the maximum bearing capacity of the girder at support C. Determine whether the girder at this location requires stiffening.
Part 6
Check the web shear capacity of the girder assuming transverse stiffeners are fitted at 2000mm centre to centre distance:
1. Confirm that the web thickness exceeds the minimum value required by AS4100
2. Confirm that the stiffened web shear capacity is satisfactory.
Part 7
Locate the critical beam bending moment and shear from load cases a to c. Check the combined bending moment and shear capacity at the critical section using the proportional method from AS4100.
Part 8
Intermediate 100x16mm transverse stiffeners are fitted each side of the girder web at 2000mm centre to centre distance. You are not required to check that these are adequate, however one pair of transverse stiffeners will be located symmetrically over the central support point C thus becoming load bearing stiffeners. You are required to check these load bearing stiffeners.
If you find that they are not sufficient then you must increase the width of the stiffeners Wx16 in 20mm increments until you have a safe design i.e. W=100, 120, 140... etc. If you are using the correct code clauses you will see that there is a quick way to estimate W.
Part 9
It was decided to weld a 450x16x2000 long cover plate to the top and bottom of the girder located symmetrically around the mid-support C.
Calculate the maximum kN/m design load required to estimate the amount of weld required to safely attach the cover plate to the girder flanges. You are not required to calculate the amount of weld.
