CYCLIC PLATE LOAD TEST - ASTM D8462 -EIE-C4021

The Cyclic Plate Load Test (CPLT) is a field performance test designed to assess the structural performance and improvement due to geosynthetic reinforcement in pavement layers. It is conducted in accordance with ASTM D8462 and is now a requirement in IRC SP 59 (2024 Amendment) for validating MIF/LCR. To simulate traffic loading through repeated cyclic loads and evaluate the: Traffic Benefit Ratio (TBR)

Test Setup & Instrumentation:

1. Bearing Plate : 300 mm diameter, 25 mm thick, rigid mild steel
2. Hydraulic Jack : Applies cyclic load at approx. 1 Hz frequency
3. Load Cell / Pressure Sensor : To measure applied cyclic load
4. Settlement Measuring Device : LVDT (Linear Variable Differential Transformer)
5. Datum Beam/Rod : Mounted with supports for LVDT, aligned level
6. Loading Frequency : 1 Hz sinusoidal/haversine cyclic load
7. Load Range : 0.5 kN (min) to 40 kN (max)
8. Nitrile Rubber Pad : 6.4 mm thick, 40A durometer (under plate for leveling)
   

Test Procedure:

1. Place the test plate over nitrile pad and ensure leveling.
2. Apply cyclic load (0.5–40 kN at 1 Hz) via hydraulic jack.
3. Monitor displacement continuously using LVDTs.
4. Continue loading until either:
5. Settlement reaches 20 mm, or
6. Permanent displacement per cycle is < 0.01 mm.
   

Data Collection:

Settlement vs Number of Cycles plotted using automated digital software.

Evaluate: TBR = NrNu\frac{N_r}{N_u}Nu​Nr​​

Equipment Description:

1. Hydraulic Jack : For cyclic loading at 1 Hz
2. Load Measuring Device : Load cell or pressure transducer
3. Bearing Plate : Mild steel, 300 mm dia, 25 mm thick
4. Nitrile Rubber Pad : 6.4 mm, 40A durometer
5. LVDT : For real-time displacement monitoring
6. Datum Beam/Rod : Holds LVDT, aligned on firm supports
7. Automated Data Logger : Records load vs displacement in real-time
8. Software : For plotting and calculating TBR, LCR, MIF