Pier Foundation Research Articles

Impact of Excavation on Adjacent Elevated Bridges and Optimization Analysis of Deformation Control

Based on the deep foundation pit project of the TOD (Transit-Oriented Development) complex of the Shaoxing North High-speed Railway Station, the influence of different construction stages on the deformation and inclination rate of the adjacent elevated bridge and its variation law are studied through field measurement and numerical simulation. The construction process is optimized by the method of reinforcement outside the pit and adjustment of preloaded axial force, and the influence of distance on elevated bridges is summarized. The results show that with the excavation of the foundation pit, the deformation of the bridge pier and bridge pile foundation gradually increases, and the deformation of the bridge piers is larger than that of the bridge pile foundations. As the depth of soil reinforcement outside the pit and the preloaded axial force increases, the maximum vertical displacement of the bridge pier and bridge pile foundations gradually decreases. The deeper the depth of soil reinforcement, the better the displacement control effect on the elevated bridge. In actual construction, it is recommended that the depth of reinforcement be taken as the excavation depth of the pit. It is obvious that the preloaded axial force is subject to the pit angle effect, and the appropriate value of the preloaded axial force should be selected according to the site conditions. The deformation of the bridge pier and bridge pile foundation generally shows a decreasing trend with the increase in the distance between the elevated bridge and the foundation pit. When the elevated bridge is close to the foundation pit, it will be affected by the pit angle effect, and the fluctuation will decrease. The conclusions drawn in the article can serve as the basis and reference for design and construction, and provide reference for similar projects.

Preliminary design of a viaduct on new Highspeed line RS2 VRT Jižní Morava

AbstractThe newly proposed high‐speed rail in Czech Republic creates a set of new challenges for engineers in design overall. In this case, the most significant challenge was to design a viaduct over several obstacles due to the crossing of Special Area of Conservation (SAC), part of Natura 2000. This aims to limit impacts in short‐term, during construction and more importantly in the long term. Construction of the viaduct will mitigate an impact to the natural surrounding area, whilst allowing immigration of its natural habitats. Nevertheless, the viaduct design and operational speeds will reach 320 km/h with possible raising to 350 km/h limit, with minimal impact within the area.Initial length of the viaduct was over 1 300 m and the main requirement given by an infrastructure manager was to design a viaduct without railway expansion joints. Due to such a long distance, the viaduct had to be separated into several dilatation segments in order to avoid the use of rail expansion joint. The most susceptible parts of SAC were in proximity of the river Šatava and surrounding wetlands. This area created an obstacle, which had to be crossed by a long span avoiding the implementation of bridge piers. Poor geological conditions close to the watercourse had to be taken into consideration for design of pier foundation, therefore the span had to be shortened to a compromised length.The final design of the viaduct consists of 16 segments, of which 14 are continuous segments and 4 are single spans. Overall, there are 29 spans over the length of the viaduct. Construction method of incremental launching had been chosen to reduce the short‐term impact in the SAC.

Arctic tern-optimized weighted feature regression system for predicting bridge scour depth

This paper presents a pioneering artificial intelligence (AI) solution – the Arctic Tern-Optimized Weighted Feature Least Squares Support Vector Regression (ATO-WFLSSVR) system to aid civil engineers in accurately predicting scour depth at bridges. This prediction system amalgamates the strengths of hybrid models by uniting a metaheuristic optimization algorithm with weighted features and least squares support vector regression (WFLSSVR). The metaheuristic algorithm concurrently optimizes all hyperparameters of constituent WFLSSVR models, resulting in a highly effective system. Validation involves a comprehensive assessment using two case studies, which include datasets of scour depths across various complexities and pier foundation types. Comparative analyses against single AI models, conventional ensemble models, hybrid techniques, and empirical methods demonstrate that ATO-WFLSSVR's reliability outperforms others in performance evaluation metrics. Specifically, for the field dataset, ATO-WFLSSVR achieves MAPE and R values of 20.92% and 0.9435, respectively, and for scour depth data at complex pier foundations, it records MAPE and R values of 6.49% and 0.9384, respectively. The automated predictive analytics underscore the robustness, efficiency, and stability of ATO-WFLSSVR compared to existing methods. This study's notable contributions include the development of an innovative optimization algorithm named Arctic Terns Optimizer (ATO), proficiency in solving high-dimensional optimization problems, and the creation of a user-friendly graphical interface system, a promising tool for civil engineers to estimate scour depth at bridges. Further testing and evaluation of ATO-WFLSSVR across diverse datasets encompassing more complex scenarios are recommended. The data and source code for this study are currently accessible at https://www.researchgate.net/profile/Jui-Sheng-Chou/publications.

Influence of the scour phenomenon on the degradation of structures: the case of bridges in Algeria

The scouring of river piles has been the main historical cause of damage and destruction of bridges over the past centuries. Today, the situation is better throughout the world due to modern techniques for carrying out work in the river (foundation work) and the ability to carry out long-distance work, reducing the number of piers in the river. But the scouring of bridge piers remains one of the most frequently recorded degradations in our country. Scouring of bridge piers is a serious issue that can threaten the stability of a bridge. It refers to the erosion of sediment (think sand, gravel, rock) around the base of a bridge pier caused by flowing water. Scour holes can undermine the foundation of the pier and expose the foundation of the pier, reducing its ability to support the weight of the bridge. This can lead to cracks in the pier itself, or even complete collapse in severe cases. On the other hand, scour is the erosion of soil around a bridge pier by flowing water. It's a major concern for bridge safety in Algeria, especially as many bridges were built before stricter seismic codes were introduced in 2010. Scour can weaken the foundation of a bridge pier, making it more susceptible to collapse during earthquakes or floods. The aim of this work is to try to study the phenomenon from different angles in order to clearly define the problem in the Algerian context, based on the analysis of several cases of work subject to scouring.

The Influence of Underwater Environment on the Effect of Underwater Drilling and Blasting for Bridge Pier Foundation

The Influence of Underwater Environment on the Effect of Underwater Drilling and Blasting for Bridge Pier Foundation

Factors Influencing Suffusion-Induced Delayed Displacement of River Bridge Piers

In recent years, local scour has occurred on the pier foundations of river bridges during heavy rain and river flooding, often resulting in bridge collapse. This study focused on the characteristic displacement, called “delayed displacement”, of the river bridge pier where the critical displacement of the piers was first observed several days after the flood when the train passed and not immediately after the flood. The authors hypothesized that one of the possible reasons for the delayed displacement is the suffusion of the supporting ground during the flood, followed by a compressive behavior due to the collapse of the soil skeleton under repeated traffic loads. Accordingly, this study performed erosion tests simulating flood and cyclic loading tests simulating train passage using a triaxial test apparatus to check the validity of this hypothesis. In some test cases, suffusion without any deformation occurred in the erosion test but deformed in the cyclic loading test just after the erosion test. This behavior matches the behavior of delayed displacement. It was also suggested that the risk of the delayed displacement becomes high when the soil skeleton was assumed to primarily comprise fine particles, and the void ratio and hydraulic gradient were high.

Experimental study on local scour protection and contact pressure of the facing water surface at the pier based on the guide pillar

The safety of pier foundations is an important issue in bridge construction, where local bridge scour is a major cause of bridge damage worldwide, exacerbated by ice sheets. This paper offers a live bed scour experimental investigation that assesses the impacts of the new anti-scour device guide pillar of different sizes on geometric properties of scour, downflow velocity distribution, and turbulence intensity around the pier under different flow velocities and roughnesses, and to select the optimum installation position and size of the guide pillar. The results demonstrate that the guide pillar has a considerable effect on the scour hole and downflow around the pier, and the maximum reduction rate of scour depth is 59.3% in the optimal installation position (2d). By arranging distributed thin-film pressure sensors on the pier and measuring the pressure distribution on the facing water surface of the pier and the position of the center of gravity, this paper analyzes the distribution characteristics of the water flow force on the pier and the impact resistance of the guide pillar to the pier scour. The study found that the guide pillar reduces the water flow force by 61.3% without considering the effect of hydrostatic pressure.

Railway Bridge Runability Safety Analysis in a Vessel Collision Event

Bridges connecting islands close to the coast and crossing the sea have been attracting the attention of several researchers working in the field of train–bridge interactions. A runability analysis of a bridge during the event of a ship impact with a pier is one of the most interesting and challenging scenarios to simulate. The objective of the present paper is to study the impact on the running safety of a train crossing a sea bridge as a function of different operational factors, such as the train travelling speed, the type of impacting ship, and the impact force magnitude. Considering train–bridge interactions, a focus is also placed on wheel–rail geometrical contact profiles, considering new and worn wheel–rail profiles. This work is developed considering a representative continuous deck bridge with pier foundations located on the sea bed composed of six spans of 80 m. Time-domain simulations of trains running on the bridge during ship impact events were carried out to quantify the effect of different operating parameters on the train running safety. For this purpose, derailment and unloading coefficients, according to railway standards, were calculated from wheel–rail vertical and lateral contact forces. Maps of the safety coefficients were finally built to assess the combined effect of the impact force magnitude and train speed. The present investigation also showed that new wheel–rail contact geometrical profiles represent the most critical case compared to moderately worn wheel–rail profiles.

Sustainability and Resiliency Investigation of Grouted Coupler Embedded in RC ABC Bridge Pier at Vehicle Impact

Increased occurrences of natural and man-made dynamic loading caused by high strain rate dynamic impact load have been recently reported. Different statistical results indicate that vehicular impacts occur more frequently compared to the other dynamic loads. However, existing literature primarily focuses on enhancing survivability and determining damage levels specifically in relation to faster bridge construction methods used as an accelerated bridge construction (ABC). In this context, the present study investigates the dynamic behavior of a commonly used connection type in ABC, namely grouted coupler that connects pre-cast elements like bridge piers and foundations. To execute the research, both the static and dynamic performance of grouted couplers embedded in pier foundation subjected to high strain rate loading incurred by high velocity vehicular impact are examined. A representative non-traditional reinforced concrete (RC) bridge pier is selected for the study with the standardized geometry and selected material properties. The use of splice sleeves as coupler materials and specified cross-sectional hollow cast iron cylinders filled with high strength concrete grout is employed for developing Finite Element (FE) modeling, extracting data from published journals. A commercial software, ANSYS, has been utilized to develop FE models to capture post impact respective static and dynamic behaviors, and the simulation results are then compared with the analytical. This also includes determining material performance via FE simulations. By considering dynamic loading, the dynamic impact factor (DIF) has been evaluated for the reinforcing steel bar adjacent and embedded into the coupler. In addition, dynamic simulations, and material modulus in demand to sustain impact are determined. Thus, the research necessitates mesh-independent sensitivity studies to investigate DIF corresponding to the precise outcomes. The findings of this study manifests valuable information that aids to opt for the suitable coupler connections, considering material properties, and adequate post impact execution. Consequently, it will serve as a useful design tool for design offices, structural practitioners, and forensic structural engineers.

Study on estimation of natural frequencies of pier foundations according to the progress of scouring

Study on estimation of natural frequencies of pier foundations according to the progress of scouring

Defects detection of pier and abutments foundations: an overview of a recent experience in Basilicata (Southern Italy)

Piers and abutments are bridge supports temporarily or permanently immersed into the water, that may suffer erosion and scour phenomena. As known, the latter involves different processes at different spatial scales not easy to investigate in a combined approach, such as: contraction scour, local scour, gradation of the soil bed, river channel dynamic, climate change and hydrological forces. To this, it should be added that piers/abutments are highly exposed to environmental actions, such as earthquake, landslides and floods that may seriously compromise their stability and, consequently, lead the bridge or an its portion to an out-of-service, or else to a failure. Therefore, it is important to properly identify and assess defects extent and severity on piers and abutments, in order to evaluate their conservation status, and to formulate a judgment for ranking priorities within a multi-level and multi-criteria framework, such as the recent guidelines issued by the Italian Ministry of Infrastructures and Transport. To this regard, in this work an overview of some significant defects related to piers and abutments, with particular emphasis to the ones due to the interaction with the water flow, are illustrated and commented. They are collected in an on-going campaign of inspections performed in the Basilicata region (South of Italy), concerning bridges falling within State Roads networks. Comments are made from a structural and hydraulic point view, in order to highlight the inspected defects importance within the Classes of Attention, according to Italian Guidelines for bridges.

Liquefaction evaluation of large pier foundations by undisturbed sampling method called GS sampling for coral pebble mixed soil

Liquefaction evaluation of large pier foundations by undisturbed sampling method called GS sampling for coral pebble mixed soil

Impact analysis of repeated improper treatment of bridge site slopes to bridge across

The bridge site slope in Zhengjiawan has been renovated several times in response to the adverse geological conditions of the Zhengjiawan ancient landslide (ZAL) in China. However, improper control and treatment measures have caused the structural failure of the Zhengjiawan bridge (ZB). Based on long-term field monitoring data of rainfall, temperature, bridge deformation, and bridge site slope displacements, this paper analyses the impact of repeated improper treatment on bridge site slopes to bridge across. Furthermore, it summarized the interrelationship between bridge deformation and bridge site slopes under natural rainfall and improper treatment measure conditions, and proposed a set of solutions for bridge site slope control and treatment. The results show that the destruction of ZB is primarily attributed to the deformation of ZAL, natural rainfall is the main trigger controlling the intermittent creep of the ZAL, while the construction of anti-slide pile and deviation rectification of bridge abutment result in significant deformation of ZAL. The deformation of ZB and ZAL were synchronous, and the monthly displacement difference ranged from 0.18 to 5.19 mm. The failure of the ZB structure resulting from the ZAL is attributed to the insufficient shear strength of the weak loose soil comprising the landslide, which fails to withstand the sliding force induced by continuous heavy rainfall. Additionally, the original anti-slide pile inadequately controls the deformation of the landslide. By setting the second-row anti-slide pile, adding the cross-sectional area of the bridge pier foundation, and installing drainage pipes, the safety of the bridge is effectively guaranteed. The control and treatment of ZAL show that preventing bridge pier deformation should be prioritized followed by controlling and treating bridge site slopes, and this study provides insights into interactions between unstable landslide treatments and bridge structures which may serve as a reference for similar projects.

Seismic performance of multi-span continuous reinforced concrete bridges considering flood-induced scour effects

Flood-induced scours near the pier foundation are an adverse phenomenon that may cause the collapse of bridges. However, in the seismic design of bridges, the scour impact is commonly ignored when evaluating the seismic response. This study aims to quantify the effect of flood-induced scours on nonlinear static and dynamic behaviors of typical reinforced concrete bridges. For this regard, three-dimensional finite element models of two- and three-span bridges with a multi-cell box girder, circular column bent, and extended pile-shaft foundation are first developed, where the column bent is modeled considering the material and geometry nonlinearity. The interaction between the soil and structure is also accounted for by using soil spring models. By considering different scour depths, the modal, static pushover, and dynamic time-history analyses of the bridges in both directions are investigated. It is observed from the modal analysis that the fundamental periods of the bridges increase with the increase of scour depth. In addition, the results in terms of the column drift ratio show that scour may increase the seismic damage to the bridges, which transfers damage from the column bent to the pile-shaft foundation. The findings of this study exhibit the significant effect of the scour on the seismic damage of reinforced concrete bridges; therefore, it is recommended that this phenomenon should be considered in the bridge seismic design.

Monotonic uplift behavior of anchored pier foundations in soil overlying rock

Monotonic uplift behavior of anchored pier foundations in soil overlying rock

A case study on the water-cooling pipe scheme in concrete early curing stage

Modelling of early curing stage of a bridge pier foundation pile cap of 4.5m thick, to be constructed at Betong division, Sarawak was carried out to verify scheme of water-cooling pipe can meet temperature specifications in which concrete must not reach a peak temperature of 70°C, and differential temperature at core and surface of concrete must not exceed 25°C. Modelling was carried out using transient heat transfer finite element analysis programme and by treating the pile cap as a concrete solid body, assuming no heat generation nor thermal conductivity of reinforcement bars. The result shows that the cooling scheme is feasible to meet temperature limitations of the specifications.

Material quantities and estimated construction costs for new elevated IRC 2015-compliant single-family home foundations

Residential foundation selection is critical for the lifetime performance of the project, but the type of foundation selected can depend on cost. This study aims to compare the new construction costs of residential slab-on-fill and four types of crawl space foundations for residential projects by quantifying the material quantities for each and exploring the effect of building characteristics on material quantities and total costs. The building characteristics selected are size (139 m2, 186 m2, and 232 m2), footprint aspect ratio (1:1, 1:2.5, and 1:5) and first floor elevation (0 m–1.2 m in 0.3 m increments). We find that material quantities and total costs change not only with building size and elevation, but also with footprint aspect ratio. Applying 2022 RSMeans Building Construction Cost data, the results show that for any building size, aspect ratio, or elevation, raised wood flooring on pier foundations ($118–$180 per m2) and slab on fill ($103–$211 per m2) are the least expensive, while crawl space foundations with stemwalls are the most expensive ($147–$280 per m2). The results of this study can be used by residential builders, developers and designers in evaluating foundation costs and design alternatives. The methodology may also be adapted for use in other applications such as flood mitigation or energy efficiency projects or environmental sustainability assessments.

Identification of vertical restraint stiffness of foundation for continuous-beam bridges

With the progress of engineering technology, the natural frequency of structures can be easily obtained by dynamic testing. If the relationship between the fundamental frequency and the constraint stiffness is analysed, the constraint stiffness of the foundation can be identified. To this end, the vertical vibration of piers is first carried out, and a dynamic identification method for constraint stiffness is proposed. Relying on a project example of a bare pier, the vertical fundamental frequency of the test pier is measured by the pulsation method. Then finite-element software is used to establish a test pier model. The stiffness identification is simulated in the completion stage by adding elastic support and concentrated mass on the top of the model pier. The results show that the difference between the identification results of the bare pier and the calculated value according to the empirical formula is only 2.97%. The error of the identification results obtained by simulating the completion stage is less than 2.34%, and decreases with the increase of the constraint stiffness of the pier top. This method is highly accurate and therefore suitable for identifying the vertical restraint stiffness of the foundation of constant section piers of continuous beam bridges.

Refined Simulation Study on the Effect of Scour Environments on Local Scour of Tandem Bridge Piers

Ice cover is a natural phenomenon unique to rivers in cold regions, and its existence is one of the reasons for the collapse of structural foundations of bridge piers across rivers. In order to understand the influence of different scouring environments on the hydrodynamics and sand bed morphology in the local scour holes around bridge pier foundations, this paper simulates the dynamic evolution process of the local scouring of tandem combination piers under open-flow and ice-cover environments, based on a turbulence model using the Reynolds-averaged Navier Stokes (RANS) method and a sediment transport model considering the slope collapse effect, respectively. This study also takes the vortex flow and shear stress distribution at different characteristic moments of the pier perimeter section as the penetration point to analyze the effect of the influence law of the scouring environment on the morphology and relative time scale of the scour hole, and makes a detailed comparison with the results of the indoor flume test. The results of this study show that: for local scouring in open-flow conditions, sediment initiation is doubly inhibited and the hydrodynamic forces in the scouring hole are weakened; the local scouring caused by ice cover contributes to the total scouring of the submerged pier within its coverage area, which significantly increases the depth and range of the local scouring hole; and, although the interaction of turbulent eddies and shear stress on the pier side is the main dynamic mechanism of the scouring generated around the pier, the two have a strong correlation. The results of this study, obtained by accurately quantifying the amount of eddies and shear stress around the pier, are the basis for the reasonable estimation of the maximum local scouring depth, which can provide a reference for the study of the evolution of the riverbed around submerged structures in cold areas and is essential to avoid structural damage to the piers and reduce the economic loss of traffic..

A new model developed by multigene genetic programming for the temporal evolution of bridge pier scour

Forecasting the time development of scour depth at bridge pier foundations is of great significance to mitigate or avoid the potential failure of bridges. Presently, several models have been developed to predict the scour depth at the base of bridge piers in the case of flood events. This study summarizes existing models for the temporal evolution of bridge pier scour and divides these studies into semiempirical models and empirical models, as well as artificial intelligence models. Several experimental data sets collected from previous studies, 665 points in total, are used to develop a new multigene genetic programming (MGGP) model for temporal scour depth at a circular bridge pier. In addition, independent data, 899 points in total, from previous studies and new physical modeling tests are applied to evaluate the behaviours of existing models, as well as the newly developed MGGP model. It is shown that the MGGP model has good prediction capability when compared with existing empirical and mathematical models.