Falling Weight Deflectometer

Standards

SHRP-LTPP AASHTO R32 FWD；JTG 3450－2019;T0953-2008; JTT1125-2017;JJG133-2017

Introduction

The Falling Weight Deflectometer (FWD for short) is a special equipment used to evaluate the bearing capacity of pavement. It starts the drop weight device through the computer-controlled hydraulic system, so that the drop weight of a certain mass falls freely from a certain height, and the impact force acts on the bearing plate and transmits it to the road surface, thereby imposing a pulse load on the road surface, resulting in instantaneous deformation of the road surface. Sensors at different distances from the measuring point detect the deformation of the surface of the structural layer, and the recording system transmits the signal to the computer, that is, the dynamic deflection and the deflection basin generated under the action of the dynamic load are measured.

Compared with the traditional Beckman beam measurement deflection, the drop-weight deflection is easy to use, fast, safe, labor-saving, simulates the actual situation to apply dynamic loads, and is suitable for long-distance and continuous measurement. After analysis and comparison, the US Federal Highway Administration confirmed that FWD is a better dynamic load assessment equipment for pavement bearing capacity, and selected FWD as an important equipment for pavement strength assessment in the implementation of SHRP plan.

Features

Easy to set up test parameters, the number of deflection drop weights, the weight lift height and the impact load can be set before the test, which is converted by the built-in load height relationship

The data acquisition software can display the current deflection and load curve of each drop weight in real time; later, the data processing software can be used to view the load and deflection time history curve of the effective drop weight

Hydraulically controlled mechanical locking device for safe detection

Specifications