Bond Beam
Bond Beam
(OP)
Hi everyone,
During the construction of a one story building a conflict on the architectical plans has been discovered between the doors and louvers lintel elevation and bond beam elevation.
The contractor wants to stop the bond beam where it meets the lintels and add a small bond beam above the lintel level rather than add another course and build a continuous bond beam above the lintel course.
My argument is that the bond beam must be continuous throughout the perimeter of the building but the project architect thinks that the contractor proposal is acceptable.
Any ideas if there is a back up supports that bond beam must be contentious.
Thank you
During the construction of a one story building a conflict on the architectical plans has been discovered between the doors and louvers lintel elevation and bond beam elevation.
The contractor wants to stop the bond beam where it meets the lintels and add a small bond beam above the lintel level rather than add another course and build a continuous bond beam above the lintel course.
My argument is that the bond beam must be continuous throughout the perimeter of the building but the project architect thinks that the contractor proposal is acceptable.
Any ideas if there is a back up supports that bond beam must be contentious.
Thank you






RE: Bond Beam
RE: Bond Beam
Richard L. Flower, P. E., LEED Green Associate
RE: Bond Beam
The main function of the bond beam at the top of the wall is to provide a solid masonry element to distribute any added point loads into the classic distribution pattern for masonry construction.
Usually, the bond beam does not pass through a control joint unless it is permitted to have a slip joint (greased end) to allow longitudinal movement, but not allow vertical or out-of plane wall movement. This allows the necessary movement and control where the movement will be so there are no random shrinkage or temperature cracks. T%he location of the control joint above and below the opening should be determined by the designer to maintain aesthetics.
I am basing this on my assumption of the building construction assumption and some standard practice. I could be wrong if the wall in not CMU single wythe or a block/brick cavity wall.
Dick
Dick
Engineer and international traveler interested in construction techniques, problems and proper design.
RE: Bond Beam
RE: Bond Beam
You still have to be concerned about a control joint, so the treatment of the horizontal rebar in the bond beam remains.
Dick
Engineer and international traveler interested in construction techniques, problems and proper design.
RE: Bond Beam
RE: Bond Beam
An expert is a man who has made all the mistakes which can be made in a very narrow field
RE: Bond Beam
The wall is CMU single wythe and the steel lintel at the same elevation of the bond bbeam at top of the CMU wall.
Thanks
RE: Bond Beam
Hokie-
When I suggested a concrete lintel, my thinking was to have the bond beam and lintel one in the same.
RE: Bond Beam
Richard L. Flower, P. E., LEED Green Associate
Senior Structural Engineer
Complere Engineering Group, Inc.
RE: Bond Beam
RE: Bond Beam
Richard L. Flower, P. E., LEED Green Associate
Senior Structural Engineer
Complere Engineering Group, Inc.
RE: Bond Beam
1. What are the over-all building dimensions (height, width and length).
2. What is the wall panel or open wall spacing and what are the opening heights/locations relative to the wall elevation. I assume (bad word) that the louvers are higher on the wall unless there is floor ventilation/evacuation.
3. What is the wall construction? - materials, thickness, etc.
This is necessary to avoid the myopic analysis similar to the three blind men independently examining an elephant with one hand, no sight and ended up with no agreement.
Unless the building is very small there is always some provision to accept the inevitable movement. I observed a load bearing back wall of a 600' long, 12-14' high commercial/industrial building that had no provision for movement in the wall, but there were 8 man doors (7' high opening) and a continuous 16" deep bond beam/lintel with 4 -#6 bars continuous. Upon investigation, cracks were observed at one edge of each opening. After that, there were cracks at the midpoint of each remaining panel between each of the openings. After the first set of natural cracks, there was another generation of cracks to further subdivide the panels for the temperature and humidity conditions. - There was also on continuous horizontal crack immediately below the continuous bond beam/lintel. The CMUs used were very low shrinkage (less than 1/4 of that allowed for the Type I units at the time) and dry. The architects and engineer lost all further business with the very large client because of the water leakage caused by the 600' horizontal crack - During my 40 years experience in the U.S. and elsewhere, I have seen similar, but far more obvious cases of movement such as long term brick expansion on a 7 story reinforced concrete frame apartment to where the differential movement (concrete shrinkage & brick expansion)it became impossible to open windows for ventilation or emergency access.
You have to look at the big long term picture of the structure, materials and movements that can create problems reflecting back on the professional design. - If not, you may mistakenly identify and elephant for a snake like the blind man.
My comments, as I originally mentioned, were based on the information provided and the information so far really has not been sufficient for more than a quick "boilerplate" solution.
The bottom line is that you probably will not find a specific requirement on continuous steel in bond beams because of the possible detrimental visual maintenance and effects without a structural benefit. IF is is a masonry wall, the purpose of the bond beam generally is to provide a beam that provides a good bearing surface, vertical distribution of the loads into the wall below, resistance to differential movement from lateral loads and still allow horizontal movement of the wall below.
Dick
Engineer and international traveler interested in construction techniques, problems and proper design.
RE: Bond Beam
The building is 28' x 64' x 13' high. There are about 4 louvers 2'x2' located all the way at the top of the wall and thier lintels are at the same level as the bond beam.
the wall is 12" CMU.
Thanks
RE: Bond Beam
RE: Bond Beam
You have a 1 story rectangular building. You have 12"cmu walls 13' high. I'm guessing you are in SDC A, B, or C. Your walls span vertically with reinforcing at some spacing and you have a single bond beam at the top of the wall- I'm guessing ladder reinforcing at 16" o.c. for horizontal S&T.
These louvers are at the top of the wall (13') and cut your continuous bond beam. If your cmu is your lat force resisting system (cmu shear walls) and this top bond beam has to handle your chord force, then you need to figure how your diaphragm load is going to get into your shear walls.