一、前言一九七三年在吉林省内进行了一次公路桥梁调查,发现各县修建的中、小跨径梁式桥中,以微弯板工字组合梁桥较多,但看到绝大部分的工字梁有明显而较多的裂纹,且挠度大,车辆通过时振动利害。为了进一步发挥此种桥型用钢省、施工方便的长处,改进其不足,一九七八年我们将简支的微弯板工 I. Preface In 1973, a road and bridge survey was conducted in Jilin Province. It was found that in the medium and small span beam bridges constructed in all counties, there were more beam bridges with slightly bent plates, but most of the beams The I-beam has obvious and more cracks, and the deflection is large, the vehicle passes the vibration interest. In order to give full play to the advantages of this type of steel bridge construction and construction, and to improve its shortcomings, in 1978,