Structural load testing is an engineering practice that involves subjecting a new or existing structure—such as a bridge, floor, pile foundation, or anchor—to controlled amounts of force to verify its ability to withstand specified design loads and ensure compliance with safety codes. This physical, empirical test provides tangible data on a structure’s actual behaviour, including deflection, deformation, and stress distribution, which is vital for validating theoretical design models and identifying potential weaknesses before a failure occurs. Loads are typically applied using large dead weights (like steel plates or water-filled bags) or, more commonly, precisely controlled hydraulic jacks acting against a reaction frame.

The accurate measurement of the applied force is critical and is accomplished using two main types of instruments:

• > Load Cells (Force Transducers): The most essential device is the Compression Load Cell (often a high-capacity canister or column type), which is placed directly in line with the hydraulic jack to measure the exact compressive force being applied to the structure or foundation. For testing anchors, rock bolts, or tiebacks, Annular (Centre-Hole) Load Cells are used, allowing the anchor cable to pass through the centre while measuring the tensile load. These rugged, high-capacity strain gauge-based devices ensure the force is known with high precision.
• > Weighing Instruments (Data Acquisition): The electrical signal mV from the load cell is connected to a sophisticated Data Acquisition System (DAS) or a specialized Digital Weighing Indicator. This instrument provides the real-time weight/force reading, performs necessary signal conditioning and filtering, and often logs the data continuously alongside other sensors (like LVDTs for measuring displacement/deflection) to create a detailed, time-stamped profile of the structure’s response under stress for later analysis and reporting.