Study On Construction Control Technology And Dynamic Characteristics Of Long-Span Steel Box Arched Bridges

In recent years, the long-span steel box arched bridge developedrapidly in China, thus many world records have been created. Someadvanced construction methods have promoted the rapid development ofthe construction of long-span steel box arched bridge, and corresponding tothese construction methods, some studies on key technologies ofconstruction control have obtained many fruitful achievements.Simultaneously, some detect theories and application studies of bridgedynamic characteristics have also obtained many achievements and havebeen widely applied to practice.This paper takes Yunnan Xiaowan Bridge, Chongqing CaiyuanbaBridge and Guangdong Foshan Dongping Bridge, etc, as the projectbackground, for these bridges are very distinct. This paper does in-depthresearches on the key technologies of construction control of all kinds ofmain construction methods referring to the steel box arched bridge.Meanwhile, we do in-depth researches on the detect theory and applicationof bridge dynamic performance during the constructing and service periods.The main work includes several aspects as follows:(1)Regarding to the steel box arched bridge, the arch ribs of whichwere constructed by using construction craft of the slanting pulls thebuckle and hang method, this paper proposed two kinds of controllingparameter solution method based on arrival for one pull: elastic-rigiditystrut method and sequential adjustment iterate-inverted removalhierarchical comprehensive method. They both can solute installation forceof buckle and pre-lifting simultaneously. For elastic-rigidity strut method,this paper derive the installation cable force of buckle cable and pre-liftingcalculation formula in the assemble process of steel box arch rib based onbasic principles of the force method. Two kinds of controlling parametersolution methods based on arrival for one pull have been appliedsuccessfully to construction monitoring of many domestic long-spanbridges, which has proved the reliability and applicability of the method.(2) Regarding to construction monitoring key technologies whichwere applied to steel box arched bridge that adopted vertical rotary construction method, this paper did system researches based on FoshanDongping bridge which adopted vertical rotary construction methodwithout buckles and its weight in the horizontal rotary is the heaviest in theworld. In allusion to structure alignment changes because of constructionscheme alterations of Dongping bridge, under the thought of arrival for onepull, we proposed an series of accurate control method of multi-objectvertical rotary construction without buckles with least squares procedure,and gained satisfactory result. We established perfect rotary constructionmonitoring system and resolved troubles of closing multi-joining pointaccurately in vertical rotary process, thus we forecasted pulling force in thehorizontal rotary correctly, checked security of structure in rotary process,solved the troubles of real-time stress monitoring and pre-warning of thelifting tower with synchronism wireless monitoring date-collecting system,these ensure the success of rotary construction.(3) This paper proposed a testing method of cable force of rigidsuspension bar test based on combined frequency testing and theoryanalysis. It solved the transcendental equation of different terminalcondition rigid suspension bar cable force and the frequency byprogramming composition with the determinant search method. In allusionto H shape rigid suspension bar, this paper proposed a frequency testmethod established on the simplified modal which considered axial force.And calculated the pull force of suspenders by measuring cross rumblespectrum of suspenders of Dongping bridge. This method can take theinfluence of opening web into account, compared to results whichcalculated by finite element method, the outcomes proved that this methodis effective and accurate.(4) Regarding to the structure features of construction process andservice stage of the steel box arched bridge, this paper proposed a bridgemodal experiment new method which adopted the fixed reference point andmove gathering quake signal under the environmental motivation, and wetook modal experiment to steel box arch bridge such as Yunnan Xiaowanbridge, Dongping bridge, the test results provided basic date for finiteelement model updating.(5) This paper proposed a hierarchical modified FE model technologycombined dynamic and static based on the theory of the modified finite element model. This paper modified initial finite element model in servicestage and established the reference finite element model of bridge healthmonitor and security evaluation based on the experiment data of thedynamic and static test of Dongping bridge. This method can use the testdata of the structure static-dynamic fully and obtain the better modalcorrection effect compared to the updating method based on singledynamic or static. It could reduce optimization scale, times of iteration andobtain more satisfied correction results compared with one-time modifiedFE model technology combined dynamic and static.