Development of Innovative Block Charts for a Box-Type Cross Drain with a Constant Width for Various Depths of Soil Cushion

Abstract

A cross-drain structure provides an opening under a highway. Cross drains must be provided transversely under highway embankments to cross obstructions such as canals, streams, and natural depressions. A cross drain is categorized according to its shape, such as an arch, slab, or box. The size of the cross drain is based on the width and depth of the obstruction. The maximum width of the cross drain is restricted to 6 m by the Indian Road Congress (IRC) standard. The National Highway Authority of India (NHAI) has set a target of constructing 39 km of roads per day. An average of two to three cross drains are required per kilometer length of highway, depending upon the topography. Thus, per day, 78 to 117 cross drains must be designed and constructed. To achieve this target, cross-drain sections should be standardized. This paper deals with cross-drain design in reinforced cement concrete (RCC) with a constant clear width of 1.5 m and a cushion of 0 to 6 m of soil over the cross drain. The vertical opening and invert levels (ILs) are decided according to hydraulic requirements, existing ground levels (EGLs), road profile, and site constraints. The cushion variable depends on the highway profile and the EGL at the cross-drain location. This paper focuses on the analysis and structural design of box-type cross drains. We used the STAAD_PRO (version 8i) program was for analysis, and we used AUTO-CAD 2016 for the preparation of drawings and figures. We analyzed the box-type cross drain for all possible load combinations mentioned in the IRC code. We considered the maximum bending moment, shear force, and crack width criteria to design the structural elements. The graphical representation of the size and shape of structural elements for various parameters is a major outcome of the study. We summarized the required bearing capacity is in tabular format. The adoption of these standard figures will aid the design of cross drains more quickly and with reduced effort.