Abstract: A large-span and special-shaped arch bridge, comprising a main girder (2), a center abutment (11) served as a central bearing point and two auxiliary abutments (12,13) served as bearing points at two ends, wherein further comprising an arch-axis combination (3) and two arch-axis bending beams (4,5) presented as arcs projected upwards, the arch-axis combination being built on the center abutment (11) with two ends connected to the inner ends of the two arch-axis bending beams (4,5), the outer ends of the two arch-axis bending beams (4,5) being built on the two auxiliary abutments (12,13), the two arch-axis bending beams (4,5) being connected to the main girder (2) via a plurality of inhaul cables. A method for constructing said arch bridge is also disclosed.

Abstract: A portable, demountable bridge to ford rivers and the like, includes a pair of footings for supporting the bridge buried at different heights in the soil on one side of the river. The footing closer to the river receives a load in a downward direction, and the footing further from the river resists an upward force produced by the weight of the bridge and objects on the bridge. Soil located over this further footing acts as a counterweight of the bridge. At least two bridge supporting units are located over the footing closer to the river. Preferably each supporting unit includes two support tubes. A removable first bracket is fixed to each supporting unit, and a second bracket is connected to the first bracket. The panels forming a roadway track for the bridge are connected to the second bracket via a first elongated support. A second elongated support connects to the footing further from the river to the second bracket.

Abstract: The bridge includes a plurality of foldable portions or modules (M) interconnectible releasably in sequence longitudinally. Each module (M) includes a central deck member (9) and two lateral deck members (10, 11) articulated to opposite sides of the central deck member (9). Respective longitudinal beams (13-16) extend from the lower faces of the lateral deck members (10, 11) and, together with the homologous beams of the other modules (M), constitute the load-bearing trusses of the bridge in its condition of use.Conveniently, the bridge is constructed by a method of assembly which provides for the use of a load-bearing assembly structure or forestarling (S). This load-bearing assembly structure (S) is assembled in a position of assembly on a first side (B.sub.1) of the gap (R) to be spanned by the bridge and is then advanced until it reaches the other side (B.sub.2) of the gap.

Abstract: A tension-band bridge having one or more main openings (2) and possibly subsidiary openings (3), comprises a tension band (4) gripped between abutments (5) and possibly taken over supporting pillars (6). The traffic route over the bridge is disposed on a saddling (7), which bends in the longitudinal direction of the bridge, in the region of the main openings (2), while the tension band (4) can be travelled over directly in the region of any subsidiary openings (3) which may be present. The saddling which bends in the longitudinal direction of the bridge preferably consists of a latticework construction (10, 11, 12) which is rigid in the transverse direction of the tension band (4) and which is connected, in the longitudinal direction of the bridge, by means of diagonal struts (13) in each of which shock absorbers (14) are disposed.