Reconstruction of the LB bridge

Contents

Introduction

Description of the bridge

Design Task

Design solutions

Calculation of roadway slab

Calculation of constant loads per 1 linear meter of beam length

Lateral distribution of time loads

Defining Internal Forces in a Beam

Verification calculations of strength of elements

List of literature used

Introduction

The design of artificial structures in modern conditions is developing due to the development of new effective design forms, the improvement of calculation methods, the use of new materials, the use of computers for calculations, the design of bridge elements and the issuance of their working drawings.

The construction of artificial structures is improved due to the use of integrated mechanization, the organization of in-line production of elements of structures and their rhythmic installation .

The bridge is a complex, responsible and expensive structure, and therefore it is subject to a number of requirements:

Operational requirements are to ensure the reliability and durability of the bridge, traffic on the bridge should be safe and comfortable. The width of the carriageway and sidewalks should correspond to the intensity of traffic, the opening of the bridge and its height should ensure the unhindered passage of flood waters, ice drifts and shipping, the bridge structures should be strong and stable.

Production requirements: bridge structures should be industrial in manufacture, convenient for transportation and installation with transport machines and mechanisms.

Economic requirements: it is necessary that the costs and costs of the bridge are minimal.

Architectural requirements: the bridge should have a beautiful appearance. Harmonize with the surrounding area.

Environmental requirements: during construction and operation, the bridge should minimally violate the environment - prevent erosion of the banks, waterlogging of the floodplain, and prevent water pollution in the river.

Description of the bridge

The bridge over the Malinovka River on the highway "Khabarovsk - Vladivostok" in the Khabarovsk Territory is located on a straight line. Designed for load A14, NK 100. The existing size of G10 + 2x0.75m. The total width of the bridge (on the outer faces of the span beams) is 12.83m.

Roadway. Design of driving canvas: reinforced concrete slab with a thickness of 180mm; Leveling layer 50 mm thick; waterproofing with thickness of 5 mm; the protective layer reinforced by a reinforcing grid of Ø6mm with cells 100kh100mm - 75 mm thick; coating - fine asphalt concrete type B grade 2 50mm thick.

Span. Bridge diagram 12m + 40m + 12m. The spans are covered by prefabricated pre-stressed T-shaped reinforced concrete beams .

The height of the beams is 1.73 m. The width of the beam plate is 2.15 m in the axes of the ribs. The thickness of the beam plate is 0.18 m, the thickness of the rib is 0.16 m, with a widening of m in the support section to 0.26 m.

In cross section the bridge consists of 6 beams .

Bridge supports.

Onshore supports No. 1 and No. 4 prefabricated foundations of the rack type. Reinforced concrete monolithic nozzle 12.83m long, 1.5m wide, 0.8m high. Cabinet wall reinforced concrete assembly 12.83 m long; 2.02m high. Reinforced concrete prefabricated openings 2.8m long. Beams are supported by sub-trusses with a plan size of 0.6x0.8m, height variable from 0.11 to 0.15m.

Intermediate supports are massive, with a size of 12.83x1.5m. Beams rest through rubber support parts on sub-trusses of 0.6x0.8m section, with variable height from 0.11 to 0.15 m.

Support parts. Opiraniye of beams of the flying building is carried out on rubber basic parts: ROCh CO 20x40x9,81,1.

Deformation joints. Deformation seam on supports of closed type: seam is covered with galvanized sheet and filled with mastic, on which protective layer and layer of roadway covering are laid.

Railing, barrier safety fences. Railing on the bridge is metal with a height of 1.1m.

The safety fence on the bridge is barrier, the spacing of the posts is 1.5m with a height of 0.75 m; on approaches - barrier, rack spacing from 1.5 to 2m.

Regulatory facilities. Regulatory structures consist of cones. The cones of the bridge are reinforced with reinforced concrete slabs 1000x1000x100mm, and are monolithic with cement mortar. At the base of the cones slopes there is a monolithic concrete stop 0.4m wide, 0.6m high.

Design Task

The need to increase the size of the carriageway from road category III to category II.

Concrete grade reduced from design B45 to B30.

Necessity of construction of sidewalks with width 1.25m.

The need to strengthen the span of the bridge due to the loss of strength in the normal section by 20%, in the inclined section by 30%.

Design solutions

Disassembly of the bridge bed.

Arrangement of rough surface of reinforced concrete slab with thickness of 2 cm, with subsequent cleaning and treatment of surface of slab of span beams with material MASTERSEAL 501.

The device for combining between the "old" and "new" reinforced concrete of the roadway slab using flexible anchors with a planted head.

Laying of cast-in-situ reinforced concrete slab of concrete B20 on top of the existing slab with projection of cantilevers for sidewalks by 0.075m (strengthening of strength in normal section) by thickness of 100mm.

Installation of roll-on-plastic waterproofing "Technoelast Most" brand "C" with thickness of 10mm.

Laying of dense asphalt concrete type A of grade II on the carriageway with a thickness of 60mm.

Laying of crushed stone asphalt concrete ShchMA15 on the roadway with a thickness of 50mm.

Laying of fine asphalt concrete type B mark I on sidewalks 60 mm thick.

Arrangement of the bridge drainage system.

Device of drains on the surface of supports nozzles.

Reinforcement along the inclined section is carried out using strips made of carbon-plastic materials of SIKA CARBODUR type S1012 with a thickness of 100mm, installed at a distance of L/4 from the axis of support of the span (on support sections) with a pitch of 0.6m and fixed using through anchors and epoxy glue of SIKADUR type * 30.

Reinforcement of the nozzles is carried out by changing the design diagram of the structure.

Repair of bridge span beams and intermediate supports is carried out using EMACO materials, BASF concern: cleaning of the structure surface with granular slag; water-jet cleaning of structures surface under pressure of 350400atm; treatment of opened rebar frame fragments with material EMACO Nanocret AP; moistening the surface; plastering on metal mesh of structures surface with EMACO S88C material up to 50mm thick.

Installation of barrier and railing.

Иванов ГП.dwg