Proposed Two-Storey Building on Piles

Project Details

This project involves the structural design and engineering for a new build two-storey residential structure. The comprehensive scope required modern engineering solutions for a robust foundation system and reinforced concrete framework, including a detailed bar bending schedule for grade beams across a multi-grid layout (Grids A–F and 1–5). The primary structural assembly utilizes 500mm wide x 600mm deep reinforced concrete ground beams supported by an integrated piling system. The design process included a rigorous load analysis that necessitated an increase in the foundation’s pile count from 14 to 23 piles to ensure the redistribution of total structural loads. This adjustment was critical to maintain a Safe Working Load (SWL) of 160 kN per pile, preventing overstressing and ensuring long-term stability. The foundation features 300mm diameter augured piles with an assumed depth of 8 meters for tender purposes. Reinforcement specifications for the grade beams include 16mm diameter high-strength rebar (main bars) and 8mm stirrups configured in specific zones with 200mm center-to-center spacing. The structural design also incorporates steel elements, including 152x152uc23 stilts with 300x300x20mm base plates and 203uc46 floor beams. All engineering works were performed in accordance with the 2010 Building Regulations (A1/2), BS EN 206:2013, and BS 8004:2015 Code of Practice for Foundations. Special attention was given to site conditions, requiring foundations to be a minimum of 1000mm below ground level and placed below the invert level of adjacent drains.

Role

Structural Engineer/Designer

Services Provided

The scope of services included the structural design of reinforced concrete ground beams based on assumed 300 mm diameter augered piles with a safe working load (SWL) of 160 kN. The design established beam sizes of up to 450 mm wide by 600 mm deep, or smaller where feasible based on pile locations and span requirements. Reinforcement detailing was prepared in accordance with applicable UK standards (BS EN/Eurocode 2), including bar sizes, spacing, anchorage, and development lengths. The services also included the preparation of a tagged and coded Bar Bending Schedule (BBS) for fabrication and installation, together with a pile load schedule identifying load take-downs from the superstructure to verify pile loads and confirm pile spacing against the assumed SWL.