Evaluation of Static Load Test Systems for Driven Piles in Intermediate GeoMaterials

Abstract

The driven pile designs in intermediate geomaterials (IGMs) entail relatively significant levels of uncertainty because of the transitional properties of IGMs between soil and hard rock. The performance and acceptability of driven piles in IGMs are typically evaluated using dynamic load test (DLT) approaches. Even though dynamic techniques have significant technological and financial advantages, a static pile load test (SLT) is required to comprehend the static behavior of driven piles in IGMs. This study presents three distinct SLT systems (independent, integrated, and innovative) that are performed on steel H-piles driven in IGMs in Iowa, Wyoming, and Colorado, respectively. Test pile 2 (TP2) is driven into siltstone in Wyoming, whereas test pile 1 (TP1) and test pile 3 (TP3) are driven into shale in Iowa and Colorado, respectively. DLTs are conducted using Wave Equation Analysis Program (WEAP) and Pile Driving Analyzer (PDA) with a signal-matching analysis utilizing the Case Pile Wave Analysis Program (CAPWAP). The ultimate pile resistances are evaluated using six distinct failure criteria. According to the Davisson criterion, TP1 has the ultimate pile resistance of 305 kips, which is 11% and 2% less than the CAPWAP and WEAP analyses, respectively. For TP2, ultimate pile resistances based on all SLT criteria are higher than that from the DLTs, except for the 5%B criterion with ultimate pile resistance at 7% lower than CAPWAP. It is evident from TP3 that the ultimate resistances acquired from SLTs are higher than the resistances obtained from dynamic analysis.

Uplift behavior of nodular diaphragm wall: Experiment and theory

“…ρ, ρ dmin , ρ dmax Density, minimum dry density, and maximum dry density; φ, φ' Internal friction angle and effective internal friction angle of soil; δ, θ 1 , φ 1 Interfacial angle, the upper angle of the nodular part, and the corresponding angle of the nodular part projection in a polar coordinate analysis; μ Poisson's ratio; τ s , τ si Skin friction acting on non-nodular wall section, and skin friction acting on non-nodular wall unit i; Δw A, A m , A mn , A b1 , A b2 , A bn Horizontal non-nodular cross-sectional area of the NDW, total area of the tapered surface above the middle nodular part protruding on both sides, area of the wall section on either side of the middle nodular part, area of the NDW's base, total area of the tapered surface above the bottom nodular part protruding on both sides, and area of the wall section on either side of the bottom nodular part. A z1 , A z2 Effective calculation area of τ sz and 𝜏 ′ 𝑠𝑧 ; A d1 , A d2 Effective calculation area of τ sd and 𝜏 ′ 𝑠d ; a 1 , a 2 , a 3 , a 4 , a 5 a 1 = 3-4μ, a 2 = 5-12μ+8μ 2 , a 3 = 0, a 4 = 2h 2 (3-4μ-1), and a 5 = 24h 4 ; a m Radius within the soil mass at which the shear strain becomes negligible; c Cohesion; D 1 , D 2 Wall thickness, and diameter of the arc section of the middle nodular part; D r Relative density; E s , E p , E 0 , G s Compressive modulus, Young's modulus, modulus of deformation, and shear modulus; F m , F b Total resistance of middle nodular wall section, and total resistance of bottom nodular wall section; f m Mean skin friction value within the middle nodular part; f s , g s Intermediate variable for skin friction, f s = 1/K s , g s = R f /τ u , R f is the failure ratio and τ u is the ultimate skin friction; H Resultant earth force acting on the side of the soil column; h Concerning calculation depth; h i , h z , h d Height of wall unit i, and height of the middle and the bottom nodular parts; K s , K b Stiffness coefficient for skin friction and nodular resistance, respectively; k Intermediate variable for K s , k = 1.3L/B, in which B and L is the longest and the shortest side length of an NDW, respectively; l 1 Calculated height of the soil column; p k , p m , p n Earth pressure measured above the middle nodular part, at and above the bottom nodular part, k = 1, ......, c, m = 1, ......, e, n = 1, ......, h, and c, e, and h is the corresponding number of earth pressure cells; P, P', P b Initial and calculated uplift load applied on the wall top, and the force acting on the wall base; P ti , P bi Forces acting on the top and bottom of non-nodular wall unit i; P tz , P bz , 𝑃 ′ 𝑡𝑑 Forces acting on the top and bottom of the middle nodular unit, and updated forces acting on the top of the middle nodular unit after iteration; P td , P bd , 𝑃 ′ 𝑡𝑑 Forces acting on the top and bottom of the bottom nodular unit, and updated forces acting on the top of the bottom nodular unit after iteration; Q m , Q b1 , Q b2 Total earth pressure at the middle nodular part, wall base, and bottom nodular part, respectively; q bz , q sz , q bd , q sd Uniform pressure and side friction working on the upper soil cylinder surface of middle and bottom nodular parts, respectively; q b , q bu Resistance, and ultimate resistance of nodular part; R 1 , R 2 , J 1 , J 2 , M Intermediate variables for calculating displacement w based on Mindlin's theory; R b , R s Resultant force of q b , and resultant skin frictional force acting on the side of the soil column; S(z) Wall displacement at depth z; S b , S u Displacement at the nodular unit and the displacement when the ultimate nodular resistance q bu is achieved, respectively; S ti , S bi Displacement of the top and bottom of the non-nodular wall unit i; S tz , S bz Displacement of the top and bottom of the middle nodular unit; S td , S bd Displacement of the top and bottom of the bottom nodular unit;…”

“…/cable-stayed bridges, 3 and static load test piles 4 are all facing uplift requirements. Suppose these building structures do not consider the uplift performance of the foundation or take improper uplift measures.…”

Improved Wave Equation Analysis for Piles in Soil-Based Intermediate Geomaterials with LRFD Recommendations and Economic Impact Assessment

“…During the construction stage, pile performance in IGM is frequently assessed utilizing dynamic testing, such as the Pile Driving Analyzer (PDA) with a subsequent signalmatching analysis using the Case Pile Wave Analysis Program (CAPWAP) [12,13]. However, once a test or production pile is equipped with PDA sensors and driven by a pile hammer during construction, the PDA-CAPWAP analysis can be carried out.…”