Fall 2023

Peabody Library Roof Strengthening  代写建筑工程作业

The George Peabody Library opened in 1878 and has served the public continuously as a premier research library for the City of Baltimore and now as part of the Johns Hopkins University. Both ceremonial and pragmatic, the main stack room of this “Cathedral of Books” contains five tiers of ornamental cast and wrought iron balconies that are fed light from the atrium skylight above. Above the ornate ceiling and lay light, a parallel history of building technology is embodied in the spectacular Phoenix Iron trusses that span the atrium. Retrofit strengthening was designed to minimize damage to the historic truss members while accommodating the very challenging requirements of construction above the library space.

1.Provide a series of three sketches that demonstrate the evolving strengthening concept at Peabody from original configuration, to concept retrofit, to final retrofit design. The sketches should each include force arrows to demonstrate the modification of the load path to help support the existing structure, including the applied uniform load, the reactions at the exterior walls and interior columns, and force magnitudes carried by both the concept and final retrofit steel members.

a.For simplicity, assume the weight of the existing structure and snow is represented as a uniform line load (w).

b.Consider the structural truss to be the full sloping depth of structure at the side bays, and then the portion of the structure between the horizontal bottom and top chords connected by X-bracing or single diagonal tie rods within the main span. The central raised gable in the middle may be considered as just load on the truss.

c.Assume the side spans are 19 feet

d.Assume the middle span is 34 feet

e.Assume the height of the truss between the horizontal bottom and top chords is 8 feet.

f.Assume half of the load within the middle span is carried as a point load at the mid span in each of the two retrofit designs  代写建筑工程作业

Hoen Lithograph Complex – Beam Retrofit  代写建筑工程作业

2.Figure 3 depicts a timber beam at the Hoen Lithograph Complex:

a.Calculate the unfactored beam reaction that is to be supported given the following:

i.Dead load consists of 3” thick solid wood plank floor and the 10” x 16” beam self weight. Use a density of wood equal to 40 pcf (pounds per cubic foot).

iii. Beam span = 25’-0”

iv.Beam spacing = 5’-3”

b.Calculate the horizontal force in the W4x13 struts and the axial force in the tie rods.

i.Assume the vertical height between the projected low point of the tie rods and the center of the W4 struts is 16 inches.

c.Does the W4 work if its allowable compressive stress is 18 ksi?

d.Do the tie rods work if the allowable tensile stress is 0.6Fy (A36 rods per Fig 4)?

e.If the timber beams can support a shear stress of 150 psi, are we overloading the adjacent beams in shear?