| Concrete arch bridge of steel pipe arch bridge as a new structure in China is still in the development stage, there is no special code for construction and design, lack of experience and data. Concrete-filled steel tube arch bridge has revealed some problems in the use process, such as the Rainbow Bridge in Sichuan province. Therefore, in order to ensure concrete filled steel tube arch bridge, a new type of bridge structure is safe to use in its construction phase will need to monitor the bridge construction process, in addition to ensure quality and safety, as well as long-term health monitoring and maintenance of the operational phase of the bridge management leave valuable data.Based on past experience in concrete-filled steel tube arch bridge construction and control, influence in the construction of bridge structures and linear factors are:temporary load of the bridge construction, the impact of sunlight, order of main arch rib concrete poured of concrete, concrete placement volume control, bulk density, modulus of elasticity of concrete, concrete shrinkage and creep effects of control and a number of other factors, hanging suozhanglali.When the above factors are inconsistent with estimates, but cannot control objectives from the primary due to timely recognition is, the results will inevitably lead to errors in the construction of remedial measures, cause errors accumulated. Large span concrete-filled steel tube arch bridge, the bridge deck width, new structures and construction technology for complex, technical difficulty, must be amended in a timely manner according to the construction process examination results. Thus, construction inspection and control has become indispensable in the construction process of large-span bridges.Jining South outer ring widens and bridge of Beijing-Hangzhou Canal Bridge widening of the bridge is consistent with the original new bridge, arch bearing the single-hole and three steel-framed arch forms, widens bridges and old bridge on the new bore design, bridge layout10+60+90+60+54m, two bridge centre line25.3m. The bridge composed of arch rib bearing structure consists of two separate, two theoretical springing elevation is38.5metres, two transverse arch rib23.1meters, Arch axis lost21.2meters high. For catenary arch axis, m=1.2catenary parameters, calculated L=93.6m long span calculated loss is f=21.2meters high, the main arch ring of dumbbell-shaped cross section, upper and lower tube diameter is1.1meters, the two centers are1.3m intermediate to the two bar connection, Web plate70cm thick. Arch rib height2.4m wide and1.1m, Arch made of Q345qc steel, arching steel plate thickness25mm lower range, the upper wall thickness16mm, micro-expansive concrete filled C50arched circles, used in the construction of segmented relay pumping.Working mechanism of arch:arch bridge under the action of vertical loads, supports not only the vertical reaction force, but also produces horizontal thrust. Because of the existence of this horizontal thrust, Arch bending moment will be much smaller than the beam of the same span of bending moment and put pressure on the entire arch main. Stress in steel truss arch bridge upper structure mainly consists of arched, Suspender, tie rods and composition with stiffening beam.Is a steel truss arch bridge arch rib in the main load-bearing structure, and permit larger axial pressure, belonging to the eccentric rod, which features is being able to use smaller material cross section obtained larger vertical and horizontal bending stiffness, reduce weight, has greater spanning capability of arch bridge and Arch ribs each node members the flexibility advantages of changing cross sections and steel types.Boom:for axial tension Member, parallel to high-strength steel strand, can only take tensile strength using flexible hanger rods can eliminate interaction between the arch and the bridge deck, and construction is convenient.Suspender beams:major external shock loads and loads are passed to arch ribs by Suspender.Bridge monitoring focused on the pouring of concrete-filled steel tube arch rib erection and, Suspender beams and precast deck slab installation and structure system shift structures and geometry of linear control. Monitor process corresponding to the construction process, one by one, achieved through the various tests reaction parameters of structural State, compared with theoretical calculated values, found deviation, take corresponding measures timely rectification. |
