Mullion-transom walls
Construction of a mullion-transom building: a) side view, b) front view, c) vertical section, d), e) construction details; 1 - foundation, 2 - brace, 3 - door lintel, 4 - window lintel, 5 - bolt, 6 - cap, 7 - ceiling beam, 8 — slup, 9 — krokiew, 10 - plaster on boarding, 11 - floor, 12 - external formwork, 13 - legar, 14 - foundation.
The figure shows the structural system of mullion-transom walls used in frame buildings. This system is the foundation, poles, cap, struts and bolts. The foundation rests on the foundation plinth on a damp-proof insulation. The columns are placed on the foundation in the corners, and intermediate ones between them at intervals of approx. 0,8-1,2 m. At the top, the columns are connected with a cap. In the outermost fields of the wall, at the corners, braces are placed, which are taken over by horizontal forces (wind pressure) and protect the building from tilting sideways and from collapsing. The struts work in compression. Transoms are placed horizontally between the mullions, which divide the field between the cap and the sill and additionally stiffen the building. In bays without window or door openings, one or two bolts can be provided, depending on the height of the wall. Two bolts are accepted in the fields with openings: lintel and window sill.
If a two-story building is foreseen, it is then that the upper story is set on the walls and floor beams of the lower story. The structural system of the upper storey can be solved in two ways. In the first method (Lynx. d) the extreme floor beam is a cap for the ground floor wall and, at the same time, a foundation for the upper floor wall, while in the second method (rys.c) the skeleton of the lower wall does not differ from the skeleton of the upper wall. In figure d, e shows a different position of the braces in the walls of the lower and upper storey. Nothing stands in the way, that the struts in both walls are inclined in the same direction. In the presented solutions, the vertical force from the wind acting on the upper storey is taken over by the corner column.