What is simple-supported beam bridge?
Simple-supported beam bridge takes one full span girder as the main load-bearing structure whose one end is supported on movable support and another end on hinged support. As the most widely used bridge with earnest application, the simple-supported beam bridge features simple structure, convenient girder installation and stable structural internal force which not influenced by foundation deformation and temperature change.
(1) Simple-supported beam bridge is divided into two kinds as construction technology: full span type and assembly type (girder segments)
- Full span type simple-supported beam features large lateral stiffness and good stability. With the limit of lifting capacity of girder carrier, full span beam usually is poured-in-place.
- Assembly type simple-supported beam is most widely used at present.
(2) Simple-supported beam bridge is divided into slab bridge, rib plate girder bridge and box girder bridge.
Main defect
With a weak anti-seismic force, the simple-supported beam bridge will be not that safe if the beam is put on ultrahigh piers with large external force.
With increasing span, main girder internal force is increased dramatically, so is the materials consumption. Solid web girder is mainly made by steel rebar concrete and pre-stressed concrete or made by steel plate box girder, which is not economical for materials using. For self-weight of materials, the height shall be higher for larger bearing capacity with the increasing span, which increases self weight of girders. When span reaches to certain degree, internal force rising caused by self weight will exceed the increasing of bear capacity, at the time the span can not be added any more. So current main girder span for simple-supported beam bridge is 50m, it is more suitable for bridge with small and middle spans, bridge with large span will not use simple-supported beam.
