Full-scale Lateral Load Tests Research Articles

Pile Spacing Effects on Lateral Pile Group Behavior: Analysis

Using the results from three full-scale lateral pile group load tests in stiff clay with spacing ranging from 3.3 to 5.65, computer analyses were performed to back-calculate p multipliers. The p mu...

Dynamic response of laterally loaded piles in clay

The behaviour of single piles under lateral dynamic loading is critical, and has been an important field of research since the 1950s. Many analytical or semi-analytical linear and non-linear models are available to estimate the dynamic lateral stiffness, but it is essential to determine the dynamic characteristics of the soil–pile system through full-scale lateral dynamic pile load tests for important structures and for validation of existing models. This paper presents the results of field lateral dynamic load tests conducted on 33 piles of varying types–driven precast concrete, driven cast-in-situ concrete and bored cast-in-situ concrete–at different petrochemical complexes in India. The results indicate that driven precast concrete piles have stiffnesses that are four to five times higher than those of driven cast in situ piles. The lateral stiffness was also estimated using the computer program PILAY for all piles and compared with the stiffness determined from the field tests. The estimated stiffness shows good agreement with the field values for stiff clay sites, but greatly overestimates the values for soft clay sites.

Recommendations for Seismic Evaluation and Retrofit of Low-Rise URM Structures

Based on the results of a full-scale lateral load test of a two-story unreinforced masonry (URM) structure, modifications are suggested for the model implied by FEMA 356 for the in-plane analysis of perforated URM walls. These modifications allow the model to address global issues such as flange participation, overturning effects, and global rocking. In addition, changes are proposed to the pier model as well as to the definition of effective pier height. Following a description of each modification, the analysis results obtained using the proposed model and FEMA 356 are compared with experimental results. In terms of base shear resistance, the proposed model displayed an average error (absolute value) of 13% compared with an average error of 21% from FEMA 356. In addition, the proposed model also provided more accurate representation of failure modes. The improved accuracy of the proposed model is primarily attributed to the consideration of global issues. The results of a parametric analysis are also pr...

Full-Scale Cyclic Lateral Load Test of Reinforced Concrete Pier-Column

The results of a lateral load test of a heavily instrumented, monolithic drilled pier-column with dimensions that were selected to mimic a typical support system for a California highway bridge are presented. The testing involved displacement-controlled slow reversed cyclic loading to large displacements. Analysis of the test data indicated that: 1) the moment-curvature relationship for the pier was well predicted by a section analysis; 2) the modulus of the predicted load-displacement relationship for the pier-column from a beam on nonlinear foundation analysis was too low at small displacements when standard spring models were used, but predicted reasonably well when stiffer, site-specific spring models were used; 3) the analyses provided a good estimate of the failure load with either set of spring models; and 4) the plastic hinge depth and length were similar to what would be anticipated from established guidelines.

Response of 0.6m Cast-in-Steel-Shell Pile in Liquefied Soil under Lateral Loading

This paper presents results from a full-scale lateral load test on a 0.6 m cast-in-steel-shell (CISS) pile in sand liquefied by controlled blasting. Lateral loads were applied by a hydraulic actuator to simulate seismic inertial forces. The CISS pile was instrumented to provide the data necessary for back calculating lateral soil resistance and displacement. Details of the pile instrumentation and testing procedure are described. The back-calculated soil resistance and displacement are presented as p–y curves and compared to static sand p–y curves. Results from three simplified analyses are presented, where liquefied soil resistance was accounted for by modifying standard static p–y curves, and compared to measured test results. Limitations of the simplified methods are discussed. Test results show the blast induced liquefied sand did not provide resistance to lateral pile movement at displacements up to 50 mm . At displacements of sufficient magnitude, a phase transformation in the sand occurred resultin...

Behavior of Laterally Loaded Large-Section Barrettes

A barrette is a large cross section rectangular pile. Due to dependence of the flexural stiffness of the rectangular section on its orientation and the nonlinear behavior of barrette materials, loading direction affects the lateral resistance of the barrette. Recently, full-scale lateral load tests were conducted on two barrettes in Hong Kong, one ~DB1! with a cross section of 2.8 m by 0.86 m and a length of 51 m and the other ~DB2! with a cross section of 2.7 m by 1.2 m and a length of approximately 30 m. This paper aims to investigate the response of laterally loaded large-section barrettes based on the load tests, to simulate the response of the two test barrettes, and to study the influence of loading direction on the lateral response of barrettes. Nonlinear p -y curves for soils and nonlinear stress-strain relations for barrette concrete and reinforcement are used to simulate the lateral response of the test barrettes considering five loading directions. The simulations were able to capture the apparently different behaviors before and after cracking of the barrette section. Sudden increases of displacement and rotation under a small lateral load increment and reduced depths of load transfer in the ground are predicted when the barrette section cracked. Based on this study, the direction of the resultant horizontal displacement is different from the loading direction if the barrette is not loaded along the major or minor axis of the cross section.

Pore Pressure Response of Liquefied Sand in Full-Scale Lateral Pile Load Tests

Several full-scale lateral pile load tests were performed at Treasure Island in the San Francisco Bay in sand liquefied by controlled blasting. Cyclic lateral loads were applied to the foundations with displacements up to 225 mm. Piezometers were installed adjacent to, and at a distance up to 4.2 m in front of, the deep foundations. Excess pore pressure ratios observed during testing are presented for the purpose of providing insight into the behavior of liquefied soil in response to laterally loaded piles. Observed excess pore pressure ratios show that soil in the loading path of the foundations experienced a phase transformation at distances as great as 4.2 m. The soil behavior in response to lateral foundation movement is presented based on interpretation of the measured excess pore pressure response.

Response of Laterally Loaded Large-Diameter Bored Pile Groups

This paper presents results of full-scale lateral load tests of one single pile and three pile groups in Hong Kong. The test piles, which are embedded in superficial deposits and decomposed rocks, are 1.5 m in diameter and approximately 30 m long. The large-diameter bored pile groups consist of one two-pile group at 6 D (D = pile diameter) spacing and one two-pile and one three-pile group at 3 D spacing. This paper aims to investigate the nonlinear response of laterally loaded large-diameter bored pile groups and to study design parameters for large-diameter bored piles associated with the p-y method using a 3 D finite-element program, FLPIER. Predictions using soil parameters based on published correlations and back-analysis of the single-pile load test are compared. It is found that a simple hyperbolic representation of load-deflection curves provides an objective means to determine ultimate lateral load capacity, which is comparable with the calculated values based on Broms' theory. Lateral deflections of bored pile groups predicted using the values of the constant of horizontal subgrade reaction, suggested by Elson and obtained from back-analysis of the single pile load test, are generally in good agreement with the measurements, especially at low loads.

Effects of Construction on Laterally Loaded Pile Groups

Full-scale lateral load tests on a group of bored and a group of driven precast piles were carried out as part of a research project for the proposed high-speed rail system in Taiwan. Standard penetration tests, cone penetration tests (CPT), and Marchetti Dilatometer tests (DMT) were performed before the pile installation. The CPT and DMT were also conducted after pile installation. Numerical analyses of the laterally loaded piles were conducted using p-y curves derived from preconstruction and postconstruction DMT and by applying the concept of p multipliers. Comparisons between preconstruction and postconstruction CPT and DMT data and evaluation of the results of computations show that the installation of bored piles softened the surrounding soil, whereas the driven piles caused a densifying effect.

Experimental Evaluation of Lateral-Load Resistance of Pile Caps

Although pile caps have considerable ability to resist lateral loads, this resistance is often neglected in design. Published cases involving a variety of pile and cap sizes, soil conditions, and loading conditions indicate that the lateral-load resistance of pile caps can be significant, but it is difficult to generalize on the basis of these results because of the variations in conditions involved in the tests. To develop a more systematic basis for evaluating cap resistance, a field test facility was constructed to perform full-scale lateral-load tests on single piles and pile groups, with the pile caps embedded in the stiff natural soil at the site and with the pile caps backfilled with granular soil. Thirty-one tests were conducted to evaluate the lateral-load resistance of pile caps by comparing the response of pile groups with caps fully embedded and with soil removed from around the caps. The results of the tests show that pile caps provide significant resistance to lateral load. This resistance depends primarily on the stiffness and strength of the soil in front of the cap and the depth of cap embedment.

Prediction of Lateral Load Response for a Pile Group

A full-scale lateral load test of a pile group consisting of 16 (4 by 4) prestressed 76-cm-square concrete piles was conducted at Roosevelt Bridge, Stuart, Florida, during the summer of 1996. Presented are ( a) in situ test results, ( b) various p-y curves from these tests, and ( c) comparisons of various computer predictions (FLPIER, GROUP, and PIGR3D) using p-y curves tempered with results from a single-pile load test. From these comparisons, the best Class A prediction is made for the 16-pile group using FLPIER with nonlinear pile properties; p-y multipliers of 0.8, 0.4, 0.3, and 0.3 for the leading, middle, and trailing two rows, respectively; and dilatometer test—pressuremeter test p-y curves. This prediction suggests that an average load per pile of 280 kN will produce a deflection of 0.1 m (63 kips/pile at a deflection of 3.9 in.) for the test group.

A new design approach for direct embedment foundations (for power line supports)

An improved model has been developed for the analysis and design of directly embedded, single-pole transmission structures subject to high overturning moments. The model uses a multispring, nonlinear subgrade modulus approach to predict the load deflection response and ultimate capacity of direct embedment foundations placed in a multilayered soil subsurface profile, and with uniform or multilayered annulus backfill. To verify the predictive capabilities of the model, ten full-scale lateral load tests were conducted on directly embedded transmission poles. The model is described, and a comparison is made between the results of full-scale load tests and model predictions of the ultimate overturning moment capacity and load deflection behavior. The semiempirical model has been implemented in the computer program MFAD (Moment Foundation Analysis and Design) contained in EPRIs TLWorkstation. The results of 10 full-scale load tests demonstrate that the model, on the average, conservatively underpredicts ultimate moment capacity by approximately 20% and has a coefficient of variation of 12%. The model is also a good predictor of moment-deflection and moment-rotation response for well-compacted backfill materials, conservatively overpredicting deflection by approximately 16% and rotation by approximately 8%.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Design of shallow rock-anchored foundations

Full-scale uplift and lateral load tests were carried out on rock anchors and rock-anchored foundations at several sites in the Province of Ontario. Various rock types were tested, ranging from soft shale to sound limestone. The results are presented; they were analyzed and important design parameters were determined for different rock formations. Based on test results, simplified design procedures were developed for the convenience of the design engineer. Keywords: Anchors, rock, transmission lines, foundations, tests, loads, design criteria, uplift pressure.

Closure to “Pile Cap Soil Interaction from Full-Scale Lateral Load Tests”

Closure to “Pile Cap Soil Interaction from Full-Scale Lateral Load Tests”

Discussion of “Pile Cap Soil Interaction from Full-Scale Lateral Load Tests”

Discussion of “Pile Cap Soil Interaction from Full-Scale Lateral Load Tests”

Pile cap soil interaction from full-scale lateral load tests : Kim, J B; Singh, L P; Brungraber, R J J Geotech Engng Div ASCE, V105, NGT5, May 1979, P643–653

Pile cap soil interaction from full-scale lateral load tests : Kim, J B; Singh, L P; Brungraber, R J J Geotech Engng Div ASCE, V105, NGT5, May 1979, P643–653

Lateral Load Tests on Drilled Piers in Stiff Clays

The results of full-scale lateral load tests on 12 drilled piers are presented. The piers were 2 ft to 4 ft in diameter, 9 ft to 22 ft in length, and were constructed in hard, overconsolidated clayey soils. Both straight shaft and belled piers were tested and test loads of up to 600 kips were applied. Eight of the tests were conducted on level ground and four of the piers were tested on slopes ranging from 20? to 50—. Measured load-deflection data for piers on level ground are compared to computed results using existing procedures for obtaining p-y curves. Approximate procedures are proposed for analysis of piers of sloping ground. It is shown that with proper selection of soil-pile interaction parameters, reasonable predictions of load-deflection behavior of piers can be made.

Pile Cap Soil Interaction from Full-Scale Lateral Load Tests

The results of full-scale lateral load tests on three groups of six piles were published earlier in January , 1976 as Proc Paper 11849. Additional full-scale lateral load tests were performed on the same pile groups and piles after removing 4 in. of soil from under the pile caps to study the effect of the soil directly under the pile caps on the lateral capacity of pile groups. In the range of 16.66 kips/pile to 33.33 kips/pile lateral loads, the absence of the soil under the pile caps increased significantly both the lateral deflections of the pile groups and bending moments in piles.

Closure to “Full-Scale Lateral Load Tests of Pile Groups”

Closure to “Full-Scale Lateral Load Tests of Pile Groups”

Discussion of “Full-Scale Lateral Load Tests of Pile Groups”

Discussion of “Full-Scale Lateral Load Tests of Pile Groups”