Development Of Automatic Drawing System For Non-abutment Slant-legged Rigid Frame Bridges

The non-abutment slant-legged rigid frame bridge is a new type of bridge developed in our country in these more than 10 years.It has got an extensive application in th Engineering,with a lot of advantages such as reasonalbe bridge structure,well strength-accepted function,greatly crossed over ability,strong adaptability,beautiful and simple shape,and the cheaper cost,and so on.But the bridge design software about the non-abutment bridge hasn't been developed at present,and there are slso very few software which has considered the assistant design during the designing process.And the inconsistencies of the desig,calculation and drawing data can be resulted from the error of calculation and graphics because of its heavy load and numerous data during design and drawing,and not only the intensity of the work is large and the efficiency is low in manual graphics,but also the quality can not be guaranteed.Therefore,the CAD technology of non-abutment bridge is needed raringly.In order to solve this problem,this thesis study and develop the assistant design software of the non-abutment bridge—the non-abutment slant-legged rigid frame bridge parametric automatic drawing system.This thesis conceives a frame of the non-abutment slant-legged rigid frame bridge CAD system,and compares a variety method of program development,then selects the stable and efficient AutoCAD platform and uses the powerful secondary development function of VBA,finally combines the Windows visualization resources,the object-oriented VB language and the graphics disposal function of AutoCAD organically and achieve the development of system.It can avoid wrong drawing and leaky drawingwhiech is result form using AutoCAD alternating-manualdrawing,and improve the speed and the quality of program development.In this system,the following funtion are carried out during the developed process:1)Accept the parameters inputing by users into the sysetem through a friendly operation interface,and transform the types of data then make a Calculation of these data.2)Do a great deal of work about the wrong-permissibility of data input,and give a message about the wrong data,so this system can raise the accuracy of engineering.3)Druing the process of developing,make the data's transference and preservation of each module become an independent format in order that it can be transferred and calculated easily.4)Through analyzing the bridge design particularly and combining the norm of bridge design closely,developing the process of drawing strictly, ensureing the correct rate of drawing by the system.Through the application of the working examples,proves this system can reduce the workload greatly for the graphices in AutoCAD of non-abutment bridge design, greatly improve the work efficiency of the users,so it possess certain theoretical value and good engineering usefulness.Besides,the thesis can direct the further work clearly from the defect in the practical application.