Concrete Pipe Research Articles

Concrete Bedding Effect on the Behavior of Buried Concrete Pipe: Experimental Investigation

Concrete Bedding Effect on the Behavior of Buried Concrete Pipe: Experimental Investigation

Model-based PD neural network control for pipe crack sealing manipulator

This study focuses on the control of a pipe crack sealing manipulator (PCSM) for concrete pipe crack sealing, with the capability to maneuver through horizontal and vertical pipes. This PCSM is a tree-type robot with five different branches. Observation and simulation studies indicate that only the fifth branch of the PCSM effectively executed the repair operation. However, in real application, the movement of these links is hindered by disturbances and uncertainties, preventing them from behaving as intended. Hence, a robust control scheme is essential to effectively manage the links of a pipe crack sealing manipulator. To address this need, this study introduces a Model-based PD neural network control (MBPDNNC) algorithm, which is then compared against modal-based PD (MBPD), Sliding mode control (SMC) with constant plus proportional rate reaching Law (CPPRL), and super twisting SMC (STSMC). The simulation study reveals that MBPDNN is characterized by greater accuracy and less chattering compared to the contrast control methods. The main contribution of this work is the compensation of disturbance by updating the weight by using the Radial basis function neural network (RBFNN). Through observation, it is evident that the neural network yields more promising results in the presence of disturbances and uncertainties.

Monitoring of historical structural materials with computed tomography

AbstractComputed tomography (CT) is an excellent tool to solve certain engineering problems connected to material science (such as sulfate swelling, internal degradation due to freezing, and alkali silicate swelling) and to understand specific processes (frost peeling, acid action). Albeit borne and mostly used in the medical domain, CT is increasingly used in the examination of the internal structure of building materials, where degradation processes occur to the detriment of their mechanical performance and durability. This paper presents five engineering problems concerning concrete freezing and thawing, concrete at high temperatures, timber charring, spalling in asbestos‐cement pipes, and deterioration in prestressed concrete pipes due to the corrosion of metallic inserts. In each case, the degradation processes are monitored via CT, something that may be crucial in the renovation and preservation of historical structures.

Geochemistry of urban waters and their evolution within the urban landscape

Urban populations and the sprawl of urban environments are increasing in the United States as well as globally. The local hydrologic cycle is directly impacted by urban development through greater generation of surface runoff and export of water through subterranean pipes networks to surface water bodies. These pipe networks carry waters that have potentially dramatic effects on the chemistry of groundwater and surface water bodies. In this work, we sampled waters from the Olentangy River and two subterranean outfalls that flow into the river in Columbus, Ohio United States. We measured the major ion, nutrient, and dissolved silica concentrations of each water source to identify how the urban landscape impacts the chemistry of a river that travels from an agricultural landscape to an urban environment. The outfalls had elevated concentrations of all major ions (Na+, K+, Mg2+, Ca2+, Cl−, SO42-) and H4SiO4. However, the Olentangy river typically had greater NO3− and soluble reactive phosphorus (SRP) concentrations. Sources of elevated ion export include road salts and combined storm runoff (Na+, Cl−), municipal water treatment practices (K+, Na+, SO42-), and concrete pipe weathering (Ca2+, Mg2+, K+, H4SiO4, SO42-). Utilizing stable isotopes of water, δ18O and δ2H, we identified that the water in the pipe networks is typically a mix of multiple precipitation events, but there is evidence of flushing following high-volume precipitation events. The contribution of high TDS waters from subterranean urban outfalls modified the ion abundance in the Olentangy river and produces a tendency towards freshwater salinization syndrome. This is particularly apparent when comparing the chemistry of the urban Olentangy to the agricultural corridor of the river and its other source waters. This research details the transformation of a river as it flows from an agricultural to urban landscape and provides data on the chemistry of source waters that facilitate the river’s chemical changes.

Community flood risk assessment in selected areas in Muntinlupa City

The study's objective is to hopefully create a profound awareness in the city government of Muntinlupa of the plight the community is experiencing. A quantitative research design was utilized in this study. Flood risk perception: The probability of whether a retention pond, increasing the diameter of the existing reinforced concrete pipes, and or increasing the road elevation can be a permanent or a quick-fix solution is still unknown until the local government can conduct a comprehensive technical and environmental assessment of the different vulnerability factors in the community. No significant differences were found between age, years of residency, and flood risk perception. Flood risk preparedness: No significant differences existed between age, years of residency, and flood risk preparedness. Substantial differences were found between gender and flood preparedness, and they favor the male gender. Flood risk awareness: No significant differences existed between age, years of residency, and flood risk awareness. There were substantial differences between gender and flood awareness, and they favored the male gender. The study's recommendations encourage the local government of Muntinlupa to conduct a comprehensive administrative, technical, and environmental assessment of the different vulnerability factors facing the selected areas in the community.

Underground concrete pipe crack damage monitoring by the fuzzy analysis of microseism

Abstract Underground concrete pipe is critical for the safety of the urban infrastructure. Crack would lead to the accidents such as fluid spillage, ground subsidence, as well as waterlogging. Thus, it is of great significance to measure and monitor the crack of pipeline. In this research, a fuzzy monitoring method of the concrete pipe crack damage based on the microseism signal GMM (Gaussian Mixed Model) analysis was proposed. First, the multi parameters of microseism signal were extracted. Then, CRITIC (Criteria Importance Through Intercriteria Correlation) weight vector was constructed using the importance information of parameters. Further, the GMM membership matrix was created by the similarity of the probability density distribution. The crack condition was assessed by means of the fuzzy calculation between the weight vector and membership matrix. The experiment indicated that the proposed method could monitor and assess the different crack conditions in real time.

Enhancing structural durability in marine concrete piles with initial defects: RS-AAT-induced advection to suppress chloride ion penetration

Chlorine-induced corrosion in unsaturated, cracked, and delaminated reinforced concrete structures is a major cause of lifespan decline in marine wet and dry zones. Reverse-seepage and Saturation based Active Anti-corrosion Technology (RS-AAT) has the scientific basis and application potential to solve this problem due to its unique saturation and reverse-seepage effects provided by structural construction means. This study introduces an analytical framework for understanding time-dependent chloride ion permeation in concrete pipe piles, incorporating the combined impact of cracks, delamination, and RS-AAT anti-corrosion approach. The analytical approach is validated through finite element method simulations and a comprehensive 90-day indoor experiment, which simulate marine submerged and tidal conditions. Extensive parametric analysis further elucidates advection-induced suppression of chloride ion diffusion by RS-AAT in cracked and delaminated conditions, considering chloride ion diffusion coefficient and water permeability coefficient, reverse-seepage pressure, initial crack characteristics and centrifugal stratification. Results show that RS-AAT substantially inhibits chloride ion penetration and lengthens the lifespan of concrete piles, even initially cracked or delaminated. This work provides a basis for RS-AAT’s application and optimization as an innovative approach to enhancing marine concrete infrastructure.

Analytical approach for vertical dynamic responses of stiffened deep cement mixing pile in unsaturated ground

Stiffened deep cement mixing (SDCM) piles present excellent engineering performance compared with conventional pipe piles and thus are often applied to the structure foundation in coastal soft-soil area. This study intends to explore the vertical dynamic behavior of a SDCM pile in unsaturated soil by developing an analytical approach. In the proposed approach, the SDCM pile divides into two parts. The first part is considered as a composite pile formed by a prestressed high-strength concrete (PHC) pipe pile and a cement mixing pile through high-strength bonding, and the second part formed by the PHC pipe pile and an unsaturated soil column. The closed-form solution for the dynamic impedance of the SDCM pile has been determined and then verified by contrasting with the existing solutions, where the dynamic impedance is mainly characterized by dynamic stiffness and dynamic damping at SDCM pile head in the vertical direction. Numerical discussions are finally implemented to analysis the dependence of physical parameters of cement mixing pile, PHC pipe pile, and unsaturated soil on the vertical dynamic impedance of SDCM pile. It can be concluded that increasing the depth, radius and elastic modulus of the cement mixing pile at relatively low load excitation frequencies is beneficial for enhancing the vertical vibration resistance of the SDCM pile, while the reverse is true at higher load excitation frequencies. Quantitatively, under relatively low load excitation frequencies, the reinforcement depth of the cement mixing pile should not exceed 2/3 of the length of the PHC pipe pile, while its elastic modulus should be 5 ‰ to 2 % of the elastic modulus of the PHC pipe pile.

The sewer advances: How to select eco-friendly pipe materials for environmental protection

Sewer pipe materials exhibit diverse inner-surface features, which can affect the attachment of biofilm and influence microbial metabolic processes. To investigate the role of the type of pipe material on the composition and metabolic capabilities of the adhering microorganisms, three sets of urban sewers (High-Density Polyethylene Pipe (HDPE), Ductile Iron Pipe (DIP), and Concrete Pipe (CP)) were constructed. Measurements of biofilm thickness and environmental factors revealed that the thickest biofilm in CP pipes reached 2000 μm, with ORP values as low as −325 mV, indicating a more suitable anaerobic microbial habitat. High-throughput sequencing showed similar relative abundances of genera related to carbon and sulfur metabolism in the DIP and CP pipes, whereas HDPE exhibited only half the relative abundance compared to that found in the other pipes. To explore the impact of pipe materials on the mechanisms of microbial response, a metagenomic approach was used to investigate the biological transformation of carbon and sulfur in wastewater. The annotations of the crucial enzyme-encoding genes related to methyl coenzyme M and sulfite reductase in DIP and CP were 50 and 110, respectively, whereas HDPE exhibited lower counts (25 and 70, respectively). This resulted in significantly lower carbon and sulfur metabolism capabilities in the HDPE biofilm than in the other two pipes. The stability of wastewater quality during the transmission process in HDPE pipes reduces the metabolic generation of toxic and harmful gases within the pipes, favoring the preservation of carbon sources for sewer systems. This study reveals the variations in carbon and sulfur metabolism in wastewater pipe systems influenced by pipe materials and provides insights for designing future sewers.

Prediction model of maximum stress for concrete pipes based on XGBoost-PSO algorithm

Due to varying burial conditions and service environments, concrete pipes exhibit complex mechanical behavior. Existing theoretical, simulation, and test methods for determining the maximum stress of pipes have significant limitations, including excessive assumptions, low efficiency, and restricted applicable conditions. Therefore, there is an urgent need to propose a multi-factor associated method for pipe stress prediction. This paper proposed an innovative approach to finely simulate the mechanics response for concrete pipes under the coupling action of stress-seepage-fluid fields. The accuracy of this numerical simulation method was validated through full-scale test. Sensitivity analysis based on Morris sensitivity analysis theory was conducted on traffic load magnitude and speed, buried depth, groundwater table, fluid height and velocity, bedding strength, backfill strength, and pipe diameter. A dataset of “physical variables - maximum stress” for concrete pipes was established. A multi-factor-correlated prediction model of maximum stress for concrete pipe was proposed using XGBoost machine learning method optimized by Particle Swarm Optimization (PSO) algorithm. The results indicate that pipe diameter is highly sensitive; buried depth and traffic load magnitude are sensitive; groundwater table, bedding strength, and backfill strength are moderately sensitive; while fluid height, traffic speed, and flow velocity are insensitive. The XGBoost-PSO model demonstrates the highest accuracy and lowest error compared to BP, RF, and XGBoost models, with improvements in prediction accuracy of 59.6 %, 23.8 %, and 8.6 %, respectively. The model achieves RMSE of 0.118 and MAE of 0.213, demonstrating the suitability of the XGBoost-PSO model for predicting maximum stress for concrete pipes.

Migration of particles suspended in yield stress fluids: Insights from numerical simulation of pipe flow of 3D printable concrete

In this work, we present a numerical model to analyse particle migration and its impact on local rheological properties when a high-yield stress suspension like 3D printable concrete is transported through a narrow circular pipe. The particle migration is studied through the lens of suspension rheology, where the effect of local particle concentration on rheological properties is accounted for using Krieger–Dougherty-type models. 3D printable mixtures with different aggregate-to-binder (a/b) ratios and flows at various discharge rates are evaluated. It is observed that, depending on the discharge rate and a/b ratio, the flow behaviour could deviate from that expected in a Poiseuille flow of Bingham fluid owing to shear-induced particle migration. Interestingly, as a consequence of particle migration, the formation of a local unsheared region close to the pipe wall is observed, apart from the plug zone at the pipe centre in the partially unsheared pipe flow of Bingham fluids. Often, for concrete pipe flow simulation, the particle size is not small enough to warrant local treatment since the finite size of the particle is not fully reflected in the flow domain. In this work, the developed numerical model is also extended to account for the finite particle size to study the transition between the sheared and unsheared regions and assess the effect of considering finite size in our simulation. Finally, the model’s capability to predict global pressure loss in pipe flow is assessed through comparisons with experimental results.

Experimental investigation of material properties of GFRP pipe for numerical simulation of novel nuclear power plant cooling water intake system

The cooling systems of nuclear power plants are typically made of reinforced concrete water intake structures and special steel pipes, making them large, important structures that necessitate very expensive special productions. In the scope of this research, an innovative design for 4-meter diameter GFRP composite pipes used in nuclear power plant cooling systems was developed using the circular wrapping method. The composite GFRP pipe used in the study has a substantial embedment depth. For this reason, an innovative design was created using unique stiffening rings, and the impact of these rings on the overall behavior was investigated. The nonlinear numerical analysis model of the nuclear power station cooling system, which consists of three pipes with a diameter of 4 m, was then created with ANSYS finite element software using the determined material models, and the results were interpreted. As a result of the study, a composite GFRP pipe design that can be used as a cooling system in significant structures like nuclear power plants has been developed.

Enhancing acid corrosion resistance in alkaline-activated materials with water treatment residue and blast-furnace slag

This study investigates the acid corrosion resistance of an alkaline-activated material (AAM) composed of ground granulated blast-furnace slag (GGBFS) and water treatment residue (WTR) as precursors. WTR, a byproduct of the drinking water treatment process rich in aluminium and silicon, proves to be a suitable precursor for AAM after cost-effective pre-treatment involving calcination and grinding. As its low-Ca content and aluminosilicate nature of the treated WTR, the AAM incorporating WTR exhibits significant potential for improving acid resistance. This is attributed to the formation of less acid-reactive N-A-S-H gels than C-A-S-H gels in high-Ca AAMs, indicating its applicability in concrete sewage pipes where microbiologically generated acid corrosion is prevalent. In the paper, a comprehensive analysis, including mechanical performance, ion leaching behaviour, and microstructural characteristics, was conducted on mortar samples containing varying WTR/GGBFS ratios before and after exposure to sulfuric acid. Incorporating WTR up to 40 % effectively reduced acid-induced strength loss compared to neat-GGBFS AAM. The obtained results reveal that high-Ca AAMs facilitate gypsum formation during acid attack, leading to mechanical degradation. The inclusion of WTR induces a Si-rich transition layer between the corroded and intact matrix, mitigating sulfate diffusion. The release of aluminium from WTR promotes secondary precipitation of aluminosilicate, beneficially increasing the thickness of the transition layer. This thicker transition layer in the higher WTR samples is advantageous in reducing the likelihood of cracks and reducing the sulfate transportation into the intact matrix.

Bond performance of fly ash-based geopolymer mortar in simulated concrete sewer substrate

Geopolymers have been extensively explored as a promising repair material for deteriorated Ordinary Portland Cement (OPC) concrete elements. However, knowledge of the adhesion performance of geopolymer to concrete substrates is limited. This study investigates the bond performance of low calcium fly ash geopolymer (FAGP) mortar and concrete for holistic acidic environmental conditions, such as in sewer rehabilitation. The bond evaluation was conducted by slant-shear test, performed at different substrate conditions, namely Rough-Dry, Rough-Saturated, Smooth-Dry and Smooth-Saturated, to simulate the in-service condition of a typical sewer pipe wall. The standard OPC repair mortar and a commercially available proprietary geopolymer repair product (P-GP) were evaluated and compared as controls to ascertain the viability of geopolymer for repair application. The shear bond strength of FAGP mortar was found to be in the order of 14 MPa, outperforming OPC and P-GP in all substrate conditions. Even though FAGP bond strength was insensitive to roughened substrate moisture levels, the synergistic effect of smoothness and moisture condition appeared detrimental. The testing of the prototype geopolymer-coated concrete pipe under line loading showed no sign of delamination at the bond plane. OPC and P-GP exhibited a distinct bond separation, which commenced at only 20 % of the ultimate load. The acid resistance and low permeability of FAGP mortar appeared to aid in preserving the repair bond.

Seismic performance of precast UHPC pipe pile with two pile-cap beam connection types: An experimental and numerical study

To develop an effective pile foundation scheme for earthquake-prone regions, this study introduces a novel pile structure that integrates ultra-high-performance concrete (UHPC) with traditional prestressed high-strength concrete (PHC) pipe piles. The research focuses on assessing the impact of various connection forms between the pile and cap beam on the seismic performance of bridge substructures. Two 1/3-scale specimens were meticulously designed and tested: one featuring a cast-in-place (CIP) connection and the other incorporating precast assembly (PA) connection between the pipe pile and cap beam. Cyclic loading tests were conducted to evaluate the failure mode, lateral capacity, ductility, energy dissipation ability, residual displacement, rebar strain, curvature distribution and rotation of UHPC pipe piles with the two connection forms. The results indicate that the specimen with a CIP connection exhibits a higher horizontal load capacity and stronger energy dissipation ability, while the specimen with the PA connection displays superior self-centering ability, increased ductility, and causes less damage to the cap beam. Finally, finite element models were developed to analyze the effects of design parameters on the seismic performance of the pile connected by the two methods. This research may provide valuable design guidance for incorporating UHPC in pile foundations. To facilitate its practical implementation in engineering projects, further theoretical and experimental research is recommended in this paper.

Key Parameters for Assessing the Deterioration of Reinforced Concrete Pipes in Water Networks

Key Parameters for Assessing the Deterioration of Reinforced Concrete Pipes in Water Networks

Long-term performance of concrete pipes under fatigue traffic loads

In recent years, there has been a concerning increase in road collapses triggered by failures in urban drainage systems. Concrete pipes, commonly uesd in urban drainage pipelines, endure prolonged cyclic loading from traffic above. However, the mechanisms governing the long-term performance and fatigue damage remain unclear. Through conducting fatigue model box tests on concrete pipes, the effects of different fatigue loading cycles on the circumferential strain of concrete pipes were investigated. A fatigue life prediction equation for concrete pipes was proposed, and the crack propagation under various fatigue loading cycles was observed. Additionally, corresponding 3D FE models of concrete pipe-soil interaction with bell-and-spigot joints and gaskets were constructed. These models were used to explore the vertical displacements, circumferential bending moments, and circumferential stresses of the concrete pipes under different fatigue loading cycles, the damage and failure mechanisms of the concrete pipes under fatigue loading were revealed. The results indicate that the potential failure location of concrete pipes is within the inner crown of the bell under the fatigue traffic loads. The circumferential strains and crack propagation exhibiting a three-stage evolution pattern under fatigue loads. The proposed fatigue life prediction equation accurately predicts the remaining life of concrete pipes. Upon reaching 21.89 million loading cycles, the strain at the inner crown of the bell reaches 575.0 με, resulting in complete failure. Cracks on the inner crown of the bell extend inward and to the right from the middle of the joint, forming a channel for crack propagation. The vertical displacements at the crown and the circumferential bending moments of the bell and spigot exhibit rapid increases, stabilization, and subsequent declines with the increasing loading cycles. When concrete pipes undergo fatigue fracture, the maximum vertical displacement and circumferential bending moment at the bell are measured as 2.26 mm and 17.82 kN·m/m, respectively. Stress concentration at the bell and spigot during fatigue loading leads to crack propagation and convergence, causing redistribution of stress fields characterized by an initial increase followed by a decrease in the inner crown and invert of the bell.

Strain response law of large-diameter PCCPs under internal water pressure based on BOTDA

Prestressed concrete cylinder pipes (PCCPs) are widely used in trans-regional large-scale water conveyance projects, so it is of great significance to monitor their condition. In this paper, the Brillouin Optical time domain analysis (BOTDA) sensing system is used to measure the circumferential strain of PCCPs under internal water pressure. The test results show that BOTDA technology can accurately monitor the shape variable of the outer wall of the pipe. Moreover, the circumferential strain is not uniform, and there are multiple relative maxima and minima. When the internal water pressure is 1.2 MPa, the absolute maximum and minimum strain is 579.17με and 217.78με respectively. In addition, there is a positive linear correlation between the strain and the internal water pressure, but the hysteresis effect is obvious in the case of insufficient water filling. This study provides reliable experimental data for the application of distributed optical fiber sensing technology in large-diameter water pipelines.

Lateral response and failure mechanism of single and group piles in cement-improved soil

Precast prestressed high-strength concrete (PHC) pipe pile with cement-improved soil is a novel pile foundation technique that has been extensively utilized in contemporary years due to the enhanced lateral load-bearing capacity in soft grounds. However, though several studies have shown the damage mechanism of single piles with cement-improved soil, the group behavior of such pile foundations is still largely unexplored. Hence, this article aims to illustrate the lateral capacity and tension-induced failure characteristics of single and 1 × 2 group PHC piles reinforced by cement-improved soil. Extensive 3D nonlinear finite element analyses have been performed and the precision of the numerical models is confirmed by a previous experimental-numerical study. The effects of pile spacing, embedment length, and cement-improved soil thickness were examined in terms of various lateral responses and damages. Results have revealed that the addition and thickening of CIS around core piles enhances the overall pile performance and protects the core pile from excessive tensile damage. Declines in head displacement and bending moment were found to be up to 45 % and 25 % for single piles, and up to 47 % and 24 % for group piles, respectively. Moreover, the presence of CIS makes the stress distribution mechanism between the trailing and leading piles in group arrangement more uniform. Results of this study are expected to provide valuable insights for a better understanding of the damage behavior of group precast piles reinforced with cement-improved soil.

Seismic Deformation Analysis of Precast Concrete Pipe Hybrid Based on 3D LiDAR and Unmanned Aerial Vehicle Photogrammetry

Seismic Deformation Analysis of Precast Concrete Pipe Hybrid Based on 3D LiDAR and Unmanned Aerial Vehicle Photogrammetry