Three-hinged frame

Construction details of the three-hinged frame: a) general scheme, b) bolt to mullion connections and mullion to foundation connections, c) combination of half-frame bolts, d) diagram of the longitudinal brace and detail of the connection of the brace with the frame transom.

Different structural system, which uses nail connections are shown in the figure. Three-hinged frame with a span of approx. 14,0 it is the load-bearing structure of the hall building. In the longitudinal direction of the building, the frames are connected with braces (rys.d) sloped to the horizontal (section I-I) which provide the required rigidity of the structure. The construction of transoms and mullions does not differ much from the construction of nailed girders. The transoms and columns have an I-section, composed of stripes with a cross-section 6 x 22 cm and a web in the form of a cross wall made of two layers of boards with a thickness of 2,5 cm.

The half-frames are articulated in the ridge and with the foundation; Connections used do not fully correspond to typical joints, however, due to the action of not very great forces, and mainly the susceptibility of wood to deformation, may be accepted, that they act as joints.

Lattice roof truss: a) view, b) horizontal sections, c) node A, d) node B, e) node C, f) node D, g) node E.

The figure shows a truss made of logs connected by smooth or toothed rings. Spar chords, The cross-brace and the posts consist of two branches, while the remaining bars from one. The two-branch rods are connected along their length with ties (dividers). The battens are more densely placed in the compression bars, it is about reducing the buckling length of individual branches.

On the covering of medium and large span hall buildings, two are used- and three-hinged frame and arch structures, in recent fly made mainly of glued wood. Spans of glued laminated timber arches are up to 100 m, while the framework for 40 m.