GRLWEAP is a one-dimensional Wave Equation Analysis program that simulates the pile response to pile driving equipment. GRLWEAP predicts driving stresses, hammer performance and the relation between pile bearing capacity and net set per blow. In addition, it estimates the total driving time. This pile simulation and analysis allows the user to investigate which hammer is likely to be sufficient and economic for a certain pile and soil condition prior to mobilizing the hammer to the job. When Wave Equation Analysis is used instead of Dynamic Formulae, several codes and standards of practice allow a leaner foundation design translating to lower factor of safety or higher resistance factor. GRLWEAP 2010 includes drivability analysis, various stroke options for diesel hammers, soil sensitivity analysis, models for parallel or composite piles and four static analysis options. The analysis of battered (driven at an angle) piles has been enhanced in GRLWEAP 2010. When the angle is horizontal, GRLWEAP may be used to simulate the installation of culverts. GRLWEAP 2010 is available in Standard and Offshore Wave Versions. GRLWEAP Offshore Wave Version includes exclusive features designed for challenging situations (free riding hammers, nonuniform and battered piles) and special analysis options such as fatigue output tables.
What Is CaPWaP®
CAPWAP® is the most accurate analysis method to determine deep foundation capacity from pile top dynamic measurements. In pile driving analysis, there are three sets of unknowns; internal pile forces, pile motions, and external pile forces. CAPWAP is a signal matching software program that uses pile or shaft top force and velocity measurements collected by a Pile Driving Analyzer® (PDA) to extract the external deep foundation forces consisting of the static and dynamic soil resistance models.
Computes the total mobilized static soil resistance, the shaft resistence magnitude and its distribution along the shaft, and the toe resistence.
- Predicts the load-displacement behavior of the testes deep foundation.
- Calculates a simulated static load test curve under compression and tension loading.
- Computes compression and tension stresses at any point of the deep foundation.
A CAPWAP analysis is performed on a representative hammer blow or impact acquired near the end of driving or beginning of restrike testing. The basic CAPWAP procedure consists of the following steps.
- Retrieve force and velocity data measured by the Pile Driving Analyzer.
- Input the pile model of known pile material types, their lengths and cross sectional areas.
- Assume a set of soil parameters including resistance, quake, and damping.
- Perform analysis using one of the measured quantities as an input and calculate the complementary quantity.
- Compare the measured and computed complementary quantity and assess the match quality.
- If match is not satisfactory, adjust soil model and return to step 3.
- Output soil model, extrema table, plot of satisfactory match, table summarizing the deep foundation model, and simulated static load-movement curve.
CAPWAP results include the deep foundation’s mobilized total bearing capacity as well as the soil resistance distribution along the foundation length. CAPWAP graphical results includes the measured force and velocity record, the best match, the resistance distribution versus depth, and a simulated static load load- movement curve. CAPWAP numerical results include the CAPWAP summary results table detailing the resistance distribution, the dynamic soil models, match quality, and pile stress maxima. For driven piles, the CAPWAP determined soil resistance and dynamic soil models are often used to develop GRLWEAP refined wave equation input parameters and establish the pile installation criterion.
capwap® graphical results
Data Review & Analysis
Engineering firms that offer foundation testing services are sometimes challenged or even overwhelmed by the data analysis processes because of the mere quantity of analyses required in a very short time. Whether due to, competing job commitments or the complexity of the data collected in the field, some testing firms require external assistance to complete the testing process.
Tethys’s senior engineers make available their experience gathered during several decades of dynamic foundation analysis available to resolve difficult situations.
Pile Driving Analyzer (PDA) operator may collect field data and retain Tethys Engineers for the essential step of performing a CAPWAP® analysis. Tethys offers various levels of service: basic CAPWAP analysis (usually on a 24 hour turn around), additional support with data interpretation and complete reporting.