| The steel truss arch bridge was used commonly in the typhoon area, for which has strongvertical stiffness and lateral stiffness. With bridge to the longer, larger and more flexibledirection, the safety and quality problem become more and more prominent. Specifically,more uncertain factors need to be considered when constructing large span steel truss archbridge in the typhoon area. In order to make a bridge state is more consistent with the designrequirements, the crucial technique of construction control for large span steel trussed archbridges in typhoon area was studied in this paper, background with Rongjiang super-largebridge of the Xiamen-Shenzhen railway. The main research work covers the followingaspects:（1）Acomparative study of the construction program based on operational researchThe merits of the overall construction plan for the success of the construction safety andquality control plays a key role. Against currently used expert seminar for the constructionprogram selection has strong empirical and subjective characteristics, this paper tried applyingoperations research decision-making theory to the typhoon area large span steel truss archbridge construction program comparison, which selected the most concerned problems ofconstruction safety, quality, schedule, technology and cost as the five sub-goals, then overallmodeling calculation is carried on the three programs that is to be adopted, finally concludedprogram is consistent with the selected results of expert seminar. According to theconstruction program, Rongjiang super-large bridge has been successfully completed and putinto use, which to a certain extent, to verify the reliability of this method.（2）Wind resistance stability control measures set researchAt first adopted for Rongjiang super-large bridge structure coefficient and wind pressuretime history of the three component of wind tunnel tests results, the wind vibration responseanalysis was carried out on the construction stage, the results of the analysis found that: underthe effect of the typhoon, the maximum tensile stress of the main girder is bigger than one inthe construction of the temporary main load (large tonnage of the cantilever crane), and underthe action of wind load and dead weight, the maximum tensile stress of the main girderexceeds the maximum tensile stress in the steel stress allowed range; The long boom of thevortex-induced resonance and chi ZhenQi winds are less than the corresponding test windspeed. Therefore, the main girder and arch rib construction respectively adopted controlmeasures as follows: in the main girder construction stage, creatively in the long-spancontinuous steel truss beam in the process of the cantilever erection of local several temporary strengthening weak link take the following facilities: the weak oblique abdominal rod directlyattached a T section bar, attach a H form to the thinner bottom chord of the section bar fortemporary strengthening, strengthening bar and Shared by reinforcing bar bolt connectionvice, reinforced bar and main girder structure has good work performance; In the arch ribconstruction stage, innovation in using wire rope will be two pieces of arch rib and the upperchord connecting, effectively improves the derrick and arch ring stability of wind resistance inthe process of construction.（3）Stress control research of the special node in the construction processFirst comparatively calculate and analyze the differences of the most unfavorableconditions in design operating status and in the construction phase, the difference between theresults found that the internal forces vary widely, which stress on both ends of the upper chordin construction stage is operating stage respectively increased by58.6%(bearing) and73.1%(by cross in the end), so for large span steel truss, except during the design phase to verifyspecial node force of cohesion, still need to consider the construction phase of the stress.Referring to shrinkage ratio computational model of achievement than the model test,construction phase node calculation model is established and the local stress analysis wascarried out on the nodes, the results showed that the local stress of steel exceeds the maximumlocal stress in the steel stress allowed range under the most unfavorable conditions.Combining with erection process and structural features, the first meeting after the chord tospell bridge panel method was put forwarded and realized the safety and reasonable set up.Then the finite element calculation model and the reliability of equivalent loading methodwere verified by the Rongjiang bridge measured data.（4）The construction quality control study of high-strength bolts connectionTwo groups of splice plates’ friction surface under natural exposure are analyzed inexperimental study, the results concluded that resistance to sliding coefficient to reduce much,respectively from the factory measured slip coefficient of0.83and0.74to0.74and0.47, onlyslightly higher than the specification requirements before the installation of not less than0.45.In view of the force transmission ratio between the head and tail rows of connectorsaccounted for most in the total joint, the torque coefficient that effects the construction qualitycontrol were studied. And then the following solutions were recommended: In order to ensurethe quality of twist in two rows of head and tail bolts, two rows of head and tail bolts shouldbe checked in100%and the middle rows bolts could be checked in10%as specificationrequired, after the final twist of bolt detection. （5）Assembled linear control technology research of large span steel truss girderFirst assembled linear of the steel truss cantilever method was deduced, and then theerror controls in the process of construction preparation stage and in front of the assembledand the closure phase were systematically researched. In preparation stage before erection, theempirical formula for the elevation settings of temporary piers was deduced, and dependingon site conditions joint reaction force of anchor pile device was putted forward for waterbearing capacity test of temporary pier loading, which ensures the reasonable settings ofmany temporary piers; In assembling stage, temperature, wind, and the construction loaddeflection in the process of the erection of the steel beam were analyzed and correspondingcontrol measures were putted forward; In closure phase, systematic study of the closure planand a three-way adjustment measures were applied to the asymmetric double span closure,eventually the erection linear and the theory linear were good agreement which verified theapplicability and rationality of linear control methods in this chapter. |
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