The control method of rubber tyre gantry （RTG） spreader in Qingdao Port Container Terminal is logic board control,which has many shortcomings such as expensive spare parts and high faults.This paper designs a new co...The control method of rubber tyre gantry （RTG） spreader in Qingdao Port Container Terminal is logic board control,which has many shortcomings such as expensive spare parts and high faults.This paper designs a new control system using programmable logic controller （PLC） centralized control to replace the original logic board control.The new system mainly contains complete ELME spreader control scheme design,hardware selection and PLC control program development.Its field application shows that the system has characteristics of high efficiency,low running cost,easy maintenance.展开更多
In steel-concrete composite twin-girder decks, wide concrete slab would undergo significant shear lag warping effect, including positive and negative. Some researchers have investigated the positive shear lag of compo...In steel-concrete composite twin-girder decks, wide concrete slab would undergo significant shear lag warping effect, including positive and negative. Some researchers have investigated the positive shear lag of composite decks by means of one-dimensional line model, while the studies on the negative shear lag have not yet been reported until now. In this study, a new one-dimensional analytical model of composite twin-girder decks is first proposed based on the model proposed by Dezi et al. Besides slab shear lag effect and partial connection at slab-girder interface which have been included in the model of Dezi et al., the particularity of the proposed model relies on its ability to account for variation characteristic of cross-section. Verification of the analytical model is later conducted through comparison of results from the analytical analysis and elaborate FE analysis for a simply supported composite deck with increasing depth and a two-span continuous one with decreasing depth. Finally, three kinds of structural forms of composite twin-girder decks, including cantilever, simply supported and continuous decks, are selected to carry out the analysis of positive and negative shear lag behaviors by means of the analytical model. The influences of cross-sectional variation characteristic and load type on positive and negative shear lag behaviors are mainly investigated. Additionally, a new definition on effective width for considering simultaneously positive and negative shear lag behaviors is proposed. The results from the proposed analytical model and EC4 specification are compared to provide suggestions for designers and checkers. In this study, the proposed analytical model can provide a powerful numerical tool for researchers to conduct the further investigation, and the analysis on shear lag and effective width can assist in design analysis of composite twin-girder decks.展开更多
基金Shandong University of Science and Technology Spring Buds Program(No.2010AZZ170)
文摘The control method of rubber tyre gantry （RTG） spreader in Qingdao Port Container Terminal is logic board control,which has many shortcomings such as expensive spare parts and high faults.This paper designs a new control system using programmable logic controller （PLC） centralized control to replace the original logic board control.The new system mainly contains complete ELME spreader control scheme design,hardware selection and PLC control program development.Its field application shows that the system has characteristics of high efficiency,low running cost,easy maintenance.
基金supported by the Fundamental Research Fund for the Central Universities(Grant No.2015JBM069)the Research Fund for Talented Scholars of Beijing Jiaotong University(Grant No.2016RC026)
文摘In steel-concrete composite twin-girder decks, wide concrete slab would undergo significant shear lag warping effect, including positive and negative. Some researchers have investigated the positive shear lag of composite decks by means of one-dimensional line model, while the studies on the negative shear lag have not yet been reported until now. In this study, a new one-dimensional analytical model of composite twin-girder decks is first proposed based on the model proposed by Dezi et al. Besides slab shear lag effect and partial connection at slab-girder interface which have been included in the model of Dezi et al., the particularity of the proposed model relies on its ability to account for variation characteristic of cross-section. Verification of the analytical model is later conducted through comparison of results from the analytical analysis and elaborate FE analysis for a simply supported composite deck with increasing depth and a two-span continuous one with decreasing depth. Finally, three kinds of structural forms of composite twin-girder decks, including cantilever, simply supported and continuous decks, are selected to carry out the analysis of positive and negative shear lag behaviors by means of the analytical model. The influences of cross-sectional variation characteristic and load type on positive and negative shear lag behaviors are mainly investigated. Additionally, a new definition on effective width for considering simultaneously positive and negative shear lag behaviors is proposed. The results from the proposed analytical model and EC4 specification are compared to provide suggestions for designers and checkers. In this study, the proposed analytical model can provide a powerful numerical tool for researchers to conduct the further investigation, and the analysis on shear lag and effective width can assist in design analysis of composite twin-girder decks.
