LUGuy
Structural
- Dec 17, 2003
- 34
I had occasion to perform a preliminary inspection of an old hotel with composite timber and concrete floors. Was there ever a typical accepted design procedure for this type of construction? Is anyone familiar with this construction?
The building was probably built between 1905 and 1909. At this time, it is assumed that there are no plans available.
Specifically, the tension component of the floor beams consists of 8" diameter timbers. Above the timbers but still in the beam portion is an additional 4-6" of concrete placed directly above the timber, and equal to the width of the timber. Above that is a reinforced concrete slab of unknown thickness poured integrally with the beam. There are shear pins between the timber and concrete at 12" on center made of either 3/8" or 1/2" steel. They are angled at about 20-25 degrees from vertical on at least one side of the timbers.
The beams span approximately 25-30 feet and are 4' on center.
Significant cracking has been seen in the slab from above at the negative moment zone. The timbers are not continuous over this section. The slabs at midspan are mostly in good condition without cracking. Deflection of the floors at midspan averages maybe about 2".
The building was probably built between 1905 and 1909. At this time, it is assumed that there are no plans available.
Specifically, the tension component of the floor beams consists of 8" diameter timbers. Above the timbers but still in the beam portion is an additional 4-6" of concrete placed directly above the timber, and equal to the width of the timber. Above that is a reinforced concrete slab of unknown thickness poured integrally with the beam. There are shear pins between the timber and concrete at 12" on center made of either 3/8" or 1/2" steel. They are angled at about 20-25 degrees from vertical on at least one side of the timbers.
The beams span approximately 25-30 feet and are 4' on center.
Significant cracking has been seen in the slab from above at the negative moment zone. The timbers are not continuous over this section. The slabs at midspan are mostly in good condition without cracking. Deflection of the floors at midspan averages maybe about 2".
