Steel H-piles Research Articles

Maximum permissible safe length of integral abutment bridges supported by steel H-piles

The absence of a defined allowable pile ductility in integral abutment bridges (IABs) creates a critical gap in determining the maximum safe bridge length. This paper introduces a design aid procedure to assist bridge engineers in establishing the length limits of jointless bridges. Numerical and analytical approaches were used in formulating the design aid procedure. A total of 66 finite difference models were established to obtain pile equivalent cantilever length considering various design parameters (soil stiffness, pile size, pile orientation, axial compressive load, and lateral displacement magnitude). The analytical approach incorporates a strain compatibility and equilibrium model to generate moment-curvature diagrams and load-deflection curves for standard HP sections commonly used in IABs construction. The validity of the developed design aid procedure was examined and tested with available experimental and numerical results. Lateral buckling displacement capacity of HP sections ranged from 50 to 100 mm (2–4 in.). Based on these displacement capacities, length limits for IABs were established and compared with existing studies. The maximum length limits for steel integral bridges fall within the range of 162–320 m (530–1050 ft), while concrete integral bridges have limits ranging from 210 to 390 m (680–1285 ft). These limits depend on factors such as pile size, soil stiffness, and climate conditions.

Axial live load distribution among single row of piles of integral bridges

This study investigates the axial live load distribution among steel H-piles in single-span integral bridges. To achieve this, two- and three-dimensional finite-element models for various integral bridges are conducted and analysed using the structural analysis software SAP2000, to determine the maximum axial loads in steel H-piles within two- and three-dimensional models. Subsequently, axial live load distribution factors from the ratio of axial loads calculated from these models are derived. The parametric study reveals that girder spacing and pile spacing exert notable influences on the axial live load distribution among the steel H-piles in integral bridges. Then, non-linear regression analysis is employed to formulate practical equations as functions of these two parameters. These equations can effectively calculate the live load distribution factors for the piles in integral bridges. To validate the accuracy of the live load distribution factors calculated from the proposed formulae, a comparative analysis is performed with results obtained from structural analysis. The standard deviations of the ratios between these two results are found to be a mere 2%. This clearly demonstrates that the developed formulae yield highly precise estimates of axial live load effects in integral bridge piles.

Experimental and Numerical Analysis of Laterally Loaded Single- and Double-Paddled H-Piles in Clay

An efficient foundation system of single- or double-paddled H-piles (PHPs), which comprises steel H-piles fitted with specially configured steel plates (paddles), is proposed to support sound walls subjected to wind loading. The lateral responses of single-paddled (SPHPs) and double-paddled H-piles (DPHPs) installed in clay is evaluated using a comprehensive assessment of the foundation performance via a full-scale lateral load testing program, alongside extensive three-dimensional (3D) nonlinear finite element (FE) analysis. The comparison between the calculated and measured responses of the PHPs demonstrates that the developed numerical model accurately depicts the response of the PHPs under lateral load. The validated numerical model is then used to evaluate the effect of the soil consistency on the lateral response and capacity of the PHPs. The influence of the paddles’ configuration on the lateral response and capacity of the PHPs is also evaluated. Furthermore, the change in the PHP lateral stiffness due to adding a second paddle is also examined. Finally, the influence of the plates on the surrounding soil is investigated by analyzing the formation of the strain field around the pile and evaluating the extent of the soil influence zone at different plate-width-to-pile-flange-width ratios (Wp/Wf). The result of this study indicates that adding plates contributes significantly to the lateral capacity of PHPs in clay and reduces the maximum bending moment. The parametric study reveals that the top 5–6 Wp of the soil have a significant effect on the lateral response of the proposed H-pile. Based on the outcomes of the field tests and numerical analysis, optimal geometrical parameters for paddles are proposed.

Investigation of the Buckling Capacity of Concrete Encased Steel H-Piles on Highway Bridge Structures

Investigation of the Buckling Capacity of Concrete Encased Steel H-Piles on Highway Bridge Structures

Behavior of Ultrahigh-Performance Concrete Plates Encasing Steel H-Piles

Steel H-piles are exposed during their service life to wet-dry cycles in combination with salts, such as deicing, that may result in corrosion, leading to cross-sectional loss and reduction in axial load-carrying capacity. This paper proposes an innovative repair method for corroded steel H-piles using ultrahigh-performance concrete (UHPC) plates. The UHPC plates are reinforced with carbon fiber-reinforced polymer (CFRP) grids. The UHPC plates bridge the corroded segment so that the axial force bypasses the corroded segment. The UHPC are bolted to the steel H-pile using high-strength bolt connectors (HSBCs). Eleven steel H-piles bolted with UHPC plates were investigated experimentally under push-out loading to quantify the axial force that can be transferred from a steel H-pile to UHPC plates through HSBCs. The examined parameters were the UHPC plate thickness, the diameter of HSBC, and the number of CFRP grid layers. The results were compared with those predicted using different design codes and guidelines. The UHPC plates attached to the steel H-pile could transfer axial loads ranging from 35% to 98% of the steel H-piles’ ultimate axial capacity. Further, the installation of the UHPC plate on a steel pile can be completed in about 2 h with minimal equipment, making it a promising repair candidate in real-world applications.

A machine learning framework for in situ sensing of pile length from seismic cone penetrometer data

Several hundred high mast light towers (HMLTs) throughout the state of Minnesota have foundation systems, typically concrete-filed steel pipe piles or steel H-piles, with no construction documentation, e.g., pile lengths. Reviews of designs within current standards suggest that some of these foundations may have insufficient uplift capacity in the event of peak wind loads. Without knowledge of the in situ pile length, an expensive retrofit or replacement program would need to be conducted. Thus, developing a screening tool to determine in situ pile length – as compared to a bulk retrofit of all towers with unknown foundations – would provide significant cost savings. The goal of the project is to establish a non-destructive evaluation (NDE) technique, including the testing setup and data analysis algorithms, for determining in situ pile lengths by way of seismic waves. This work specifically focuses on (i) the use of ground vibration waveforms captured by a seismic cone penetrometer; (ii) three-dimensional visco-elastodynamic finite element method (FEM) used as a tool to relate the sensory data to in situ pile length; and (iii) the use of machine learning (ML) algorithms, trained with the outputs of FEM simulations, to solve the germane inverse problem. In principle, the scarcity of existing HMLT configurations with known pile depth creates an absence of field data needed to adequately train an ML algorithm. However, we demonstrate that the use of FEM simulations as proxy training data for the ML algorithms leads to a robust data interpretation scheme.

Capacity of piles subject to downdrag: a comparison of North American bridge design codes and observations from a full-scale test pile program

Negative skin friction caused by ground settlement is an important consideration for deep foundations in limit states design. However, there are inconsistencies in the methodology whereby negative skin friction and associated drag force are considered in assessing the geotechnical capacity or geotechnical ultimate limit state (ULS) in various design codes. This includes two current North American bridge design codes, the Canadian Highway Bridge Design Code, and AASHTO LRFD Bridge Design Specifications. A test pile program was developed to observe effects of ground settlement on pile settlement, capacity, and drag force. Two instrumented steel H-piles were driven through a compressible clay layer to a hard end-bearing stratum, subjected to ground settlement by constructing a 1.5 m high embankment, followed by static load testing. A load-transfer model was calibrated from the test pile program observations. Test results and the calibrated model were used to compare geotechnical ULS requirements of the two bridge design codes. It is demonstrated that drag force did not detrimentally impact pile capacity. The results showed that for conditions of the test pile program, assessing the geotechnical ULS can be more conservative when adhering to the current AASHTO LRFD Bridge Design Specifications than the Canadian Highway Bridge Design Code.

Lateral buckling capacity of steel H-piles supporting integral abutment bridges (IABs)

Integral abutment bridges (IABs) have been gaining wide popularity in the United States and neighboring countries due to the rapid increase in maintenance costs associated with conventional bridges. The elimination of expansion joints in IABs allows the thermally induced lateral demand in the superstructure to be transferred to the supporting piles. This paper aims to study the behavior of steel H-piles supporting IABs through a detailed nonlinear finite element analysis that was calibrated and validated against available experimental data. A total of 30 models were established to examine the effect of various parameters (pile size, pile orientation, pile material yield strength, pile equivalent cantilever length, and axial compressive load) on piles supporting jointless bridges subjected to a combined axial load and lateral cyclic displacement amplitude. Local buckling was the dominant failure mode for all the specimens. Furthermore, this paper reiterates the various parameters and assesses their influence through a statistical regression analysis to develop an empirical formula for calculating the lateral buckling capacity. The rationality of the developed formula was examined and tested with existing experimental data, which testified the reliability to be used for future design considerations.

Experimental Study on Seismic Response of an Integral Abutment: Steel H-Pile Structure under Quasi-Static Cyclic Loads

ABSTRACT In this paper, a quasi-static cyclic test was performed on an integral abutment-steel H-pile specimen considering the interaction of the soil with the abutment and pile in order to evaluate its seismic response. The results in terms of failure mechanism, deformation, earth pressure distribution, hysteretic behavior, backbone curve, stiffness, damping ratio, and ductility are briefly discussed. The results indicated that the interaction of the backfill soil with the abutment and pile could significantly improve the overall cyclic response of the IAJB. In addition, the integral abutment-steel H-pile structure has good ductility and energy dissipation capability.

Improved Wave Equation Analysis of Steel H-Piles in Shales Considering LRFD and Economic Impact Studies

Improved Wave Equation Analysis of Steel H-Piles in Shales Considering LRFD and Economic Impact Studies

Behavior, Performance, and Evaluation of Prestressed Concrete/Steel Pipe/Steel H-Pile to Pile Cap Connections

Better understanding of the connection between piles and pile caps/footings is needed so that future designs and design reviews can be adequately performed. This review paper presented discussions on the published experimental and analytical studies on prestressed concrete piles, steel H-piles, or steel pipe piles with cast-in-place (CIP) or precast footings, and/or pile cap connections with a focus on (1) pile embedment to achieve a fully fixed or pinned moment connection; (2) behavior of the pile embedment length when not treated by a special connection detail; and (3) reinforcement details to decrease the embedment length and develop fixity with a plain pile. The length of the pile embedment contributing to achieving a full fixity condition has a critical impact on substructure cost involving pile-to-pile cap (PTPC) connections. The design procedures involving piles subjected to lateral loading require a proper understanding of the fixity and ductility levels provided by the PTPC connections. Discussions on finite-element analyses (FEAs) were presented, including behavior predictions of the connections at both global and local levels. The study points to the need for modifications to the design of the PTPC connections in the existing standard codes/specifications.

New Static Analysis Methods and LRFD Recommendations for Steel H-Piles in Rock-Based Intermediate Geomaterials

New Static Analysis Methods and LRFD Recommendations for Steel H-Piles in Rock-Based Intermediate Geomaterials

Risks in Reuse of Highway Bridge Foundations

The average age of highway bridges in the US as of 2019 is 45 years, with almost 43% of existing highway bridges being older than 50 years and 8% of them being in poor conditions. For bridges in need of replacement, the reuse of the existing foundations can be an attractive option from economic, environmental, and mobility perspectives. However, successful planning for foundation reuse requires a detailed understanding of the risks over the service life of the bridge. This paper presents a framework to calculate the time-dependent risk of reusing an existing foundation. The methodology is further demonstrated by a case study of a bridge supported by driven steel H-piles in Bucks County, PA. The proposed framework is used to estimate the marginal cost of different reconstruction options using a time-dependent probability of failure, reliability index, and risk profile of the bridge. Results show that an alternative based on corrosion mitigation in combination with foundation strengthening has the lowest marginal risk cost and can be the most attractive option during the reconstruction of the bridge.

Longitudinal seismic response of integral abutment bridges

A finite-element (FE) investigation into the response of integral abutment bridges (IABs) to seismic loading in the longitudinal direction was conducted. An example multi-span reinforced concrete solid-slab bridge was designed and analysed using an elasto-plastic two-dimensional FE model. The bridge abutment was taken as supported on steel H-piles. The proposed FE model was found to have the capability of simulating both the bridge construction and the backfilling process using a multi-step numerical process. The bridge was examined considering various lengths and different backfill materials, and was subjected to earthquake loading. The analyses showed that the seismic response of IABs is notably affected by the bridge length. Longer bridges may be subject to higher pressures on the abutments and internal forces in the bridge structure. The stiffness and strength parameters of the backfill material may also markedly influence dynamic pressures on the abutments and internal forces in the structure. Backfill materials with greater stiffness and strength parameters may cause significant reductions in the seismic flexural stresses in both the abutments and the deck. Coupling seismic and thermal loads could be suggested for the design of IABs.

Behavior of a Pile Group Supporting a Precast Pile Cap under Combined Vertical and Lateral Loads

AbstractA half-scale field test was conducted on a pile group installed at a stiff clay site. The pile group consisted of eight steel H-piles, with a battered pile at each corner, and connected to ...

Effect of crevice morphology on SRB activity and steel corrosion under marine foulers

Localized corrosion of submerged steel H-piles was detected in a Florida bridge spanning over a brackish river. Analysis of the water showed proliferation of sulfate reducing bacteria (SRB). The steel piles had coincident heavy marine growth that may support biofilms and biocorrosion. The objective of the research described here was to identify the role of the physical morphologies of macrofouling on SRB activity and the aggravation of microbiologically influences corrosion (MIC) of submerged steel bridge. Laboratory experiments were carried out in nutrient-rich environments inoculated with SRB, with both porous and laminate crevice conditions characteristic of soft and hard marine fouling. It was confirmed that SRB proliferation can occur within the crevice environments, but aeration levels under crevices with interaction with the bulk solution can affect SRB activity. Electrochemical impedance spectroscopy provided separation of environmental parameters and surface reaction parameters for the complicated systems relating to corrosion under the porous and laminate crevice geometries.

Considerations for measuring residual stresses in driven piles with vibrating wire strain gauges

Vibrating wire strain gauges are often the preferred technology for measuring strain in driven piles. However, measuring the residual strain after pile driving is challenging to accomplish using vibrating wire gauges. The driving process can cause a shift in the no-load reading from a relaxation of locked-in manufacturing strains in the pile or relaxation of the gauge wire tension. Also, there are temperature effects from installing piles below ground. A test pile program was developed using driven steel H-piles instrumented with vibrating wire strain gauges. The piles were subjected to dynamic forces by striking against a steel plate in an attempt to relax the locked-in manufacturing strain prior to installation. The strain gauges and thermistors were connected to a data logger during pile driving to record strain and temperature changes following installation. It was observed that applying a dynamic impact to the piles prior to installation resulted in a shift of 0–5 με (microstrain). Temperature effects from installing the piles in cooler ground resulted in a shift of strain in excess of 60 με in some strain gauges. It is concluded that temperature-induced shifts to strain must be measured following pile driving to interpret residual stresses.

Influence of Macro- and Microfouling on Corrosion of Steel Bridge Piles Submerged in Natural Waters

AbstractAnomalous localized corrosion of submerged steel H-piles was detected in a Florida bridge. Microbiological analysis at the site indicated a high population of sulfate-reducing bacteria (SRB...

Effect of Source Application on Sonic Echo/Impulse Response Tests Applied to Steel H-Piles

AbstractThe sonic echo/impulse response (SE/IR) method is a versatile nondestructive method for evaluating the conditions of unknown bridge foundations. Previous studies have shown that the method ...

Line-finite-element implementation for driven steel H-piles in layered sands considering post-driving residual stresses

Driven Steel H-piles are commonly used in the deep foundation of being cost-effective and easy in workmanship. The post-driving residual stresses acting on the pile could be large when being driven in cohesionless sands, significantly affecting its compressive strength. Current design methods, mostly based on the empirical assumptions of using safety factors, are unable to consider the post-driving residual stresses on piles accurately and usually very conservative in practical applications. Such consideration is further complicated when the pile is embedded in layered sands. Moreover, the soil-structure interaction (SSI) between pile and ground medium is usually complicated in the analysis and should be appropriately considered in a successful design. This paper proposes a line-finite-element implementation method, based on the Euler-Bernoulli pile element formulations, for robustly and efficiently analyzing the driven steel H-piles in layered sands with explicitly modelling the SSI. The effects resulting from the post-driving residual stresses are considered in the total potential energy equation for generating the secant relations. The derivation procedure is elaborated with details. Consequentially, verification examples are given for validating the accuracy of the proposed method. This work would be helpful for improving the numerical efficiency and accuracy for designing the steel H-piles in layered sands.