Reinforced Concrete Masonry Wall
Reinforced Concrete Masonry Wall
(OP)
Hello Engineers,
I have a rather unique structure.
It is 13 ft wide, 19 ft long, 30 ft tall, concrete masonry, 140 mph wind, and exposure category C. It is basically a tower for the local firefighters to train maneuvering throughout a smoke-filled stair way.
As far as load and load combinations on this relatively tall and slender structure, the out-of-plane load analysis on the 8" reinforced concrete masonry walls fail at around 15 ft tall.
Now the question is if I am on the right track. I am putting reinforced 8"x16" concrete tie beams spaced at the tower base, roof, and 10 ft on center vertically. This breaks the 30 ft wall up into three 10 ft sections. I can now analyze each 10 ft vertical concrete masonry wall for out-of plane loading as three separate pinned-pinned beams. The pinned-end reactions of the vertical masonry wall become the loading on the horizontal reinforced concrete tie-beam for its design. The reactions of the pinned-pinned horizontal tie beam become the load as far as analyzing the adjacent shear wall that takes the out-of-plane wind loads into the foundation.
Does this analysis sound acceptable? Anyone having performed concrete masonry design ever get involved in finding some design to get a single wythe 8" reinforced concrete masonry wall to resist high lateral loads?
Thanks to all for your input,
JAS34
I have a rather unique structure.
It is 13 ft wide, 19 ft long, 30 ft tall, concrete masonry, 140 mph wind, and exposure category C. It is basically a tower for the local firefighters to train maneuvering throughout a smoke-filled stair way.
As far as load and load combinations on this relatively tall and slender structure, the out-of-plane load analysis on the 8" reinforced concrete masonry walls fail at around 15 ft tall.
Now the question is if I am on the right track. I am putting reinforced 8"x16" concrete tie beams spaced at the tower base, roof, and 10 ft on center vertically. This breaks the 30 ft wall up into three 10 ft sections. I can now analyze each 10 ft vertical concrete masonry wall for out-of plane loading as three separate pinned-pinned beams. The pinned-end reactions of the vertical masonry wall become the loading on the horizontal reinforced concrete tie-beam for its design. The reactions of the pinned-pinned horizontal tie beam become the load as far as analyzing the adjacent shear wall that takes the out-of-plane wind loads into the foundation.
Does this analysis sound acceptable? Anyone having performed concrete masonry design ever get involved in finding some design to get a single wythe 8" reinforced concrete masonry wall to resist high lateral loads?
Thanks to all for your input,
JAS34






RE: Reinforced Concrete Masonry Wall
RE: Reinforced Concrete Masonry Wall
Is the structure covered at roof level? How about seismic loads? Are there any other loads to be accounted for?
You mentioned about providing concrete beam. Why bring in another trade? See if you can live with a masonry beam at a lesser spacing. You may also provide reinforced bond beams all around, spaced at about 4 feet o.c. vertically. This would help the four walls to be tied together and behave as one unit.
For lateral loads, 8" thick wall can span horizontally for 13 feet.See if a 10" thick wall can span horizontally for 19 feet.
RE: Reinforced Concrete Masonry Wall
Some used lightweight block for better fire resistance in case there was potential direct fire exposure.
The real key is the continuity/connections and whether the landings can be tied into the structure.
Dick
Engineer and international traveler interested in construction techniques, problems and proper design.
RE: Reinforced Concrete Masonry Wall
RE: Reinforced Concrete Masonry Wall
DST148, to answer your questions, right now I am looking at load combinations with wind loading and also, the roof is covered. I do like your comment about concrete pours in with concrete masonry block. The concrete tie beams, an extra material, will add extra cost. The architect just included them in the prelimanary design that I am analyzing. So, can I design a horizontal reinforced concrete bond beam in the same matter as the reinforced concrete tie beam? That is to let the vertical reinforced concrete masonry act as vertical beams that tie into the horizontally reinforced masonry bond beam. The horizontal bond beam then can be designed as a horizontal beam that takes the lateral loads to the shear walls?
- JAS34
RE: Reinforced Concrete Masonry Wall
RE: Reinforced Concrete Masonry Wall
- JAS34
RE: Reinforced Concrete Masonry Wall