Materials

Research

30 pages, 12470 KiB

Open AccessArticle

On the Possibility of Using 3D Printed Polymer Models for Modal Tests on Shaking Tables: Linking Material Properties Investigations, Field Experiments, Shaking Table Tests, and FEM Modeling

by Pawel Boron, Jaroslaw Chelmecki, Joanna Maria Dulinska, Nadzieja Jurkowska, Bartlomiej Ratajewicz, Piotr Stecz and Tadeusz Tatara

Materials 2023, 16(4), 1471; https://0-doi-org.brum.beds.ac.uk/10.3390/ma16041471 - 9 Feb 2023

Cited by 2 | Viewed by 1331

Abstract

In this article, the possibility and the pertinence of using 3D printed polymeric materials for models in modal tests on shaking tables were recognized. Four stages of the research have been linked: The material properties investigation, the field experiment on the modal properties [...] Read more.

In this article, the possibility and the pertinence of using 3D printed polymeric materials for models in modal tests on shaking tables were recognized. Four stages of the research have been linked: The material properties investigation, the field experiment on the modal properties of the reinforced concrete chimney (a prototype), the shaking table tests on the modal properties of the 3D printed polymer model of the chimney, scaled according to the similarity criteria, and the numerical calculations of the FE model of the 3D printed mockup. First, the investigation of the properties of 3D printed polymer materials revealed that the direction of lamination had no significant effect on the modulus of elasticity of the material. This is a great benefit, especially when printing models of tall structures, such as chimneys, which for technical reasons could only be printed in a spiral manner with the horizontal direction of lamination. The investigation also proved that the yield strength depended on the direction of the lamination of the specimens. Next, the natural frequencies of the chimney, assessed through the field experiment and the shaking table tests were compared and showed good compatibility. This is a substantial argument demonstrating the pertinence of using 3D printed polymer materials to create models for shaking table tests. Finally, the finite element model of the 3D printed polymer mockup was completed. Modal properties obtained numerically and obtained from the shaking table test also indicated good agreement. The presented study may be supportive in answering the question of whether traditional models (made of the same material as prototypes) used in shaking table tests are still the best solution, or whether innovative 3D printed polymer models can be a better choice, in regard to the assessment of the modal properties and the dynamic performance of structures. Full article

(This article belongs to the Special Issue Seismic Design and Structures Analysis of Construction Materials)

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25 pages, 8428 KiB

Open AccessArticle

Experimental Static and Dynamic Characteristics of Recycled Waste Tire Rubber Particle–Cement–Sand Composite Soil

by Zhaoyan Li, Liping Zhang, Haiyang Zhuang and Qi Wu

Materials 2022, 15(24), 8938; https://0-doi-org.brum.beds.ac.uk/10.3390/ma15248938 - 14 Dec 2022

Cited by 3 | Viewed by 1594

Abstract

To investigate the static and dynamic characteristics of rubber–sand composite soil (RS soil) reinforced with cement, a series of triaxial compression tests and resonant column tests was performed by considering the influence of rubber content (10%, 20%, 30%, 40%, and 50%), cement content [...] Read more.

To investigate the static and dynamic characteristics of rubber–sand composite soil (RS soil) reinforced with cement, a series of triaxial compression tests and resonant column tests was performed by considering the influence of rubber content (10%, 20%, 30%, 40%, and 50%), cement content (0, 1.5, 2.5, 3.5 and 4.0 g/100 mL), and effective consolidation confining pressure (50, 100, and 150 kPa). Compared with the RS soil, the addition of cement significantly improved the shear strength of a cement–rubber–sand composite soil (RCS soil), based on an undrained shear test. The increase in cement content not only makes the elastic modulus and cohesion of the RCS soil increase but also reduces the internal friction angle of the RCS soil. With the increase in rubber content, the failure of the RCS soil samples changes from strain-softening to hardening, and the prediction equation of the initial elastic modulus of the RCS soil is given herein when the recommended cement content is 3.5 g/100 mL. The effects of rubber content, cement content, and effective confining pressure on the dynamic shear modulus and damping ratio of the RCS soil were studied via the resonant column test. The test results show that the increase in rubber content slows down the modulus attenuation of the RCS soil, but increases its damping ratio. The test results also show that the increase in cement content makes the bonding force between particles greater so that the modulus attenuation of the RCS soil becomes slower and the damping ratio is reduced. At the same time, according to the change rule of the maximum dynamic shear modulus of the RCS soil with the rubber content, when the recommended cement content is 3.5 g/100 mL, an empirical formula and recommended value of the shear modulus G_max of the RCS soil are proposed. Full article

(This article belongs to the Special Issue Seismic Design and Structures Analysis of Construction Materials)

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15 pages, 4458 KiB

Open AccessArticle

Seismic Response of Star-Type Grid Concrete Wall Structure by Numerical Modeling

by Baizan Tang, Yuying Dong, Wen Bai, Hua-Peng Chen, Haiyang Zhuang and Wenchao Deng

Materials 2022, 15(23), 8519; https://0-doi-org.brum.beds.ac.uk/10.3390/ma15238519 - 29 Nov 2022

Viewed by 1261

Abstract

Cement polystyrene shell mold (CPSM) grid concrete walls have been widely applied in the construction of low and mid-rise buildings with higher load-bearing and insulation properties. A star-type grid concrete wall was constructed based on the infill wall simplified to an equivalent diagonal [...] Read more.

Cement polystyrene shell mold (CPSM) grid concrete walls have been widely applied in the construction of low and mid-rise buildings with higher load-bearing and insulation properties. A star-type grid concrete wall was constructed based on the infill wall simplified to an equivalent diagonal bracing model. To investigate the seismic responses and behavior of a star-type grid concrete wall structure, an overall time-history numerical simulation was carried out in this paper. Typical results, including acceleration, deformation, hysteresis curve and failure pattern of this novel construction system, were interpreted. Results indicate that the star-type grid concrete wall structure has satisfactory seismic performance, including energy dissipation capacity. The structure has higher lateral stiffness and can work in an elastic state under major earthquakes. Accordingly, it is more sensitive to near-fault ground motion with higher frequency components. Meanwhile, the structural inter-story drift angle is less than the limit value of lighter damage when subjected to a super-major earthquake, and the structure presents shear deformation. The openings significantly affect the failure mode, the star-type grid concrete wall with a window (a small aspect ratio less than 1.11) conforms to shear failure, and the wall with a door (aspect ratio of 2.5) conforms to bending-shear failure. The diagonal bracing can distribute the stress in the wall, especially the concrete lattice beam, and effectively resist the lateral forces via the concrete lattice column, improving the ductility and integrity of the structural system. Full article

(This article belongs to the Special Issue Seismic Design and Structures Analysis of Construction Materials)

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17 pages, 6923 KiB

Open AccessArticle

Geotechnical Seismic Isolation System Based on Rubber-Sand Mixtures for Rural Residence Buildings: Shaking Table Test

by Zhiyong Yin, Haifeng Sun, Liping Jing and Rui Dong

Materials 2022, 15(21), 7724; https://0-doi-org.brum.beds.ac.uk/10.3390/ma15217724 - 2 Nov 2022

Cited by 7 | Viewed by 1758

Abstract

The anti-seismic problem of rural residential buildings is the weak link of seismic retrofitting in China. Recently, geotechnical seismic isolation (GSI) technology based on rubber–sand mixtures (GSI–RSM) using rubber–sand mixtures (RSM) between the structural foundation and the foundation soil has been proven to [...] Read more.

The anti-seismic problem of rural residential buildings is the weak link of seismic retrofitting in China. Recently, geotechnical seismic isolation (GSI) technology based on rubber–sand mixtures (GSI–RSM) using rubber–sand mixtures (RSM) between the structural foundation and the foundation soil has been proven to have the possibility of potential applications in rural residential buildings. Many theoretical studies exist on the effectiveness of seismic isolation of the GSI–RSM system, but few studies on either the seismic response test of model buildings placed on the RSM layer or the large-scale shaking table test exist. Therefore, this study considers a large shaking table test performed on a 1/4 single-story masonry structure model with and without a GSI–RSM system by selecting a standard input ground motion and varying input acceleration amplitudes. The test results show that the GSI–RSM system can reduce the seismic response of superstructures. The isolation effect of the GSI–RSM system is low in small earthquakes and increases with increasing earthquake magnitude. Overall, the RSM layer can filter part of the high-frequency components of the earthquake to transmit to the superstructure and consume more seismic energy by generating friction slip in the interaction with the structural foundation. Full article

(This article belongs to the Special Issue Seismic Design and Structures Analysis of Construction Materials)

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12 pages, 3159 KiB

Open AccessArticle

Experimental Study on the G_max Characteristics of the Sand-Silt Mixed Soil Materials Using Bender Element Testing

by Jiang Bian, Hao Wu, Xing Xiao, Qi Wu and Zheng-Long Zhou

Materials 2022, 15(18), 6200; https://0-doi-org.brum.beds.ac.uk/10.3390/ma15186200 - 6 Sep 2022

Cited by 2 | Viewed by 1205

Abstract

To study the small strain shear modulus (G_max) of saturated sand-silt mixed soil materials, a series of tests were conducted using the bender element apparatus, and the influences of fines content (FC), relative density (D_r), [...] Read more.

To study the small strain shear modulus (G_max) of saturated sand-silt mixed soil materials, a series of tests were conducted using the bender element apparatus, and the influences of fines content (FC), relative density (D_r), and effective confining pressure (

{σ^{'}}_{3 c}

) were taken into consideration. The test results indicate that the G_max of the mixed soil materials decreases first and then increases with the FC up to 100% with D_r = 35% and 50%, while the G_max decreases with the increasing FC when D_r = 60%. Moreover, for a given D_r, the G_max increases with the increasing

{σ^{'}}_{3 c}

, and the increase rate keeps constant under various FCs. The G_max of specimens under various FCs decreases with the increase of the void ratio (e). The decrease rate between the G_max and e differs when the

{σ^{'}}_{3 c}

is given, which is influenced by the FC. The G_max of the mixed soil materials can be evaluated by the Hardin model when the FC is determined. The best-fitting parameter A of the Hardin model first decreases and then increases as FC increases. The revised Hardin model, considering the influence of FC,

{σ^{'}}_{3 c}

, and e, can be used to evaluate the G_max for different types of sand-silt mixed soil materials. The error between the evaluated and tested G_max is less than 10%. Full article

(This article belongs to the Special Issue Seismic Design and Structures Analysis of Construction Materials)

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15 pages, 4037 KiB

Open AccessArticle

Seismic Behavior of Shear Keys Enhanced with Novel Energy Absorption Devices in Immersion Joints Based on Pseudo-Static Tests

by Xinjun Cheng, Xiang Xu, Liping Jing, Haian Liang and Jie Cui

Materials 2022, 15(13), 4579; https://0-doi-org.brum.beds.ac.uk/10.3390/ma15134579 - 29 Jun 2022

Cited by 1 | Viewed by 1514

Abstract

Shear keys are usually installed as crucial shear-resistant members of an immersion joint; thus, the mechanical behavior of the shear keys, especially under earthquake loading, deserves more attention. This paper presents a novel arc-shaped energy absorption device developed for shear keys. In order [...] Read more.

Shear keys are usually installed as crucial shear-resistant members of an immersion joint; thus, the mechanical behavior of the shear keys, especially under earthquake loading, deserves more attention. This paper presents a novel arc-shaped energy absorption device developed for shear keys. In order to verify the seismic performance of shear keys strengthened by the arc-shaped energy absorption devices, a series of pseudo-static tests were conducted, in which different axial pressures (300 kN, 400 kN) were also taken into consideration. The testing results indicated that failure mode of the shear key enhanced by the energy absorption devices was a synthesis of the oblique shear failure of the rubber blankets, the buckling of the energy absorption devices, and the concrete fracture of the shear key. In view of load-displacement hysteretic curves of testing specimens, loops of the reinforced shear keys were plumper than those from a traditional shear key. In addition, the load-bearing capacity (cracking load, yield load, peak load, and failing load) differences of the shear keys with and without energy absorption devices reinforcement under the same axial pressure were 33.0%, 36.7%, 26.0%, and 23.6%, respectively. The maximum equivalent viscous coefficient values of the shear keys with and without energy absorption devices reinforcement were 0.37, 0.38, and 0.32, respectively. The arc-shaped energy absorption devices can contribute to the hysteretic behavior of the shear keys. However, the axial pressure had a positive influence on the load bearing capacity, accumulated energy absorption capacity, and initial stiffness of the shear keys. In contrast to that, the axial pressure had negative influence on ductility ratio of the reinforced shear keys (equivalent viscous coefficient values of two enhanced shear keys were roughly equal). A reasonable stiffness scheme of an energy absorption device should be given attention during the anti-seismic design of an immersion joint. The study can provide scientific support for further study on the seismic responses of immersion joints and promote the application of earthquake control technology in immersed tunnels. Full article

(This article belongs to the Special Issue Seismic Design and Structures Analysis of Construction Materials)

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16 pages, 2233 KiB

Open AccessArticle

Degradation Law and Service Life Prediction Model of Tunnel Lining Concrete Suffered Combined Effects of Sulfate Attack and Drying–Wetting Cycles

by Feng Lu, Haiyan Wang, Lichuan Wang, Kai Zhao and Junru Zhang

Materials 2022, 15(13), 4435; https://0-doi-org.brum.beds.ac.uk/10.3390/ma15134435 - 23 Jun 2022

Cited by 14 | Viewed by 1561

Abstract

The present study explored the degradation law and service life prediction of tunnel lining concrete with different mineral admixtures under coupled actions of sulfate attack (SA) and drying–wetting (DW) cycles. The deterioration resistance coefficient (DRC) of compressive strength and influence coefficients of sulfate [...] Read more.

The present study explored the degradation law and service life prediction of tunnel lining concrete with different mineral admixtures under coupled actions of sulfate attack (SA) and drying–wetting (DW) cycles. The deterioration resistance coefficient (DRC) of compressive strength and influence coefficients of sulfate concentration, mineral admixture content, water/binder (w/b) ratio, and curing regime on DRC were studied. After that, a new service life prediction model based on damage mechanics was developed and analyzed. Results show that, by increasing the DW cycles, the DRC first increases and then decreases. DRCs of Ordinary Portland cement (OPC), fly ash (FA), and ground granulated blast-furnace slag (GGBS) concrete linearly decrease with the increase of sulfate concentration, while the silica fume (SF) concrete displays a two-stage process; by increasing the admixture content, the DRCs of FA and GGBS concrete exhibit two distinct stages, while the SF concrete depicts a three-stage process; increasing the w/b ratio linearly decreases the DRC; the DRC of curing regime was sequenced as standard curing (SC) > fog curing (FC) > water curing (WC) > same condition curing (SCC). Based on the experimental results, the service life prediction model is applied and validated. The validation results show that the proposed model can accurately predict the lifetime of concrete with different mix proportions. Furthermore, it is found that the mineral admixture can effectively improve the lifetime of concrete, and the composite mineral admixture is more effective than a single mineral admixture in improving the lifetime of concrete. Full article

(This article belongs to the Special Issue Seismic Design and Structures Analysis of Construction Materials)

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16 pages, 2941 KiB

Open AccessArticle

Characterizing the Phase-Structure and Rheological Response-Behavior of Multi-Walled Carbon Nanotubes Modified Asphalt-Binder

by Yongyi Li, Weijie Zhang, Chaoen Yin and Xiaorui Zhang

Materials 2022, 15(13), 4409; https://0-doi-org.brum.beds.ac.uk/10.3390/ma15134409 - 22 Jun 2022

Cited by 2 | Viewed by 1234

Abstract

In this study, the phase-structure and rheological response-behavior of multi-walled carbon nanotube (MWCNTs) modified asphalt-binder (MWCNTs-MA) were measured and quantified in the laboratory. The changes in the molecular dynamics due to MWCNTs modification were simulated and quantified based on the intermolecular interaction energy [...] Read more.

In this study, the phase-structure and rheological response-behavior of multi-walled carbon nanotube (MWCNTs) modified asphalt-binder (MWCNTs-MA) were measured and quantified in the laboratory. The changes in the molecular dynamics due to MWCNTs modification were simulated and quantified based on the intermolecular interaction energy computations, electrostatic potential surface analyses and phase-structure modeling of the asphalt-binder matrix. The rheological properties such as the asphalt-binder viscosity and complex modulus, of both the base and modified asphalt-binders, were determined using the standard Brookfield viscometer (BV) and dynamic shear rheology (DSR) test devices, respectively. In comparison to the base asphalt-binder, the corresponding BV-DSR test results exhibited higher viscosity and complex modulus for the MWCNTs modified asphalt-binder, with reduced sensitivity and susceptibility to temperature variations. From the study results, it was observed that MWCNTs significantly improved the rheological properties and high-temperature performance of the asphalt-binder. Overall, the study has demonstrated that MWCNT modified asphalt-binder has great promising potential for application and usage as a road-pavement material, particularly with respect to mitigating the high temperature related distresses such as rutting. Full article

(This article belongs to the Special Issue Seismic Design and Structures Analysis of Construction Materials)

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26 pages, 15009 KiB

Open AccessArticle

Seismic Response Evaluation of High-Steep Slopes Supported by Anti-Slide Piles with Different Initial Damage Based on Shaking Table Test

by Hongyu Chen, Guanlu Jiang, Xinhui Zhao, Dan Zhu, Yong Liu and Hongcheng Tian

Materials 2022, 15(11), 3982; https://0-doi-org.brum.beds.ac.uk/10.3390/ma15113982 - 3 Jun 2022

Cited by 5 | Viewed by 1755

Abstract

In order to study the instability development process of the slope reinforced by anti-slide piles under earthquake conditions, the dynamic response characteristics of the slope are usually taken as the main characteristics, and the model test and numerical simulation are the main research [...] Read more.

In order to study the instability development process of the slope reinforced by anti-slide piles under earthquake conditions, the dynamic response characteristics of the slope are usually taken as the main characteristics, and the model test and numerical simulation are the main research methods. In this paper, a shaking table model test is designed and completed to investigate the influence of anti-slide piles with different initial damage on the failure mode of high and steep slope under earthquake conditions. The changes in velocity, strain and natural frequency during slope vibration are tested in combination with cloud maps when sinusoidal waves of different accelerations with a peak value of 5 Hz are applied. Thus, the differences of slope failure development process and dynamic response characteristics are obtained. The experimental results show that the anti-slide pile with different initial damage has obvious influence on the slope instability process. Under the condition of good anti-slide pile quality, the failure development of the slope behind the pile is limited to soil sliding on top of the slope, slope sliding and overburden sliding; the front slope foot of pile mainly forms shear belt and local sliding. With the decrease in the initial mass of the anti-slide pile, the slope failure develops into topsoil sliding, slope sliding and deep integral sliding; analogously, the failure of the slope in front of the pile develops into a whole slip along the slip belt. The natural frequency cloud map can directly reflect the damage location of the slope, and the frequency change rate is positively correlated with the cumulative shear strain. It shows that the macro-failure characteristics of the model slope change well when the natural frequency is used as the sensitive index to measure the influence of vibration on the model slope. The threshold value of the natural frequency change rate can distinguish different development stages of the slope; 1% is the threshold value of stage II, and 1.5% is the threshold value of stage III. Full article

(This article belongs to the Special Issue Seismic Design and Structures Analysis of Construction Materials)

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13 pages, 2412 KiB

Open AccessArticle

Mechanical Properties and Strengthening Mechanism of Dredged Silty Clay Stabilized by Cement and Steel Slag

by Jian Shi, Shengnian Wang, Wenzhe Cao, Jun Su and Xingjin Zhang

Materials 2022, 15(11), 3823; https://0-doi-org.brum.beds.ac.uk/10.3390/ma15113823 - 27 May 2022

Cited by 6 | Viewed by 1541

Abstract

The high moisture content and low strength of dredged soft soils result in significant difficulties in directly reutilizing them in engineering. Improving their mechanical properties effectively and achieving re-utilization with the maximum benefit in engineering is the key to disposing of dredged soils [...] Read more.

The high moisture content and low strength of dredged soft soils result in significant difficulties in directly reutilizing them in engineering. Improving their mechanical properties effectively and achieving re-utilization with the maximum benefit in engineering is the key to disposing of dredged soils with high moisture content. This study investigated the influences of cement and steel slag ratio, moisture content, the maximum particle size of steel slag, and curing age on the compressive strength of dredged silty clay in a plastic flow state. The performance improvement of dredged silty clay stabilized with cement and steel slag was discussed by comparing to related previous studies. The strengthening mechanism of dredged soils stabilized with cement and steel slag was explored by microstructural observation. The results show that when the ratio of cement to steel slag was 9:6; namely, using steel slag to replace 40% of cement, the strength properties of dredged silty clay stabilized by cement and steel slag could ensure the minimum requirements of the project greater then 100 kPa, and their economics could achieve the best results. The finer the particle size of steel slag was, the better the stabilization effect was. The compressive strength of dredged silty clay stabilized by cement and steel slag with particle sizes of less than 0.075 mm was 1.06 times, 1.10 times, and 1.16 times that of 0.25 mm, 1 mm, and 2 mm and increased linearly over curing ages earlier than 28 days. The compressive strength of dredged silty clay stabilized by cement and steel slag cured for 28 days was 2.44 times, 1.59 times, and 1.36 times that of 3, 7, and 14 days, respectively. The evolution of microstructural characteristics showed that the internal pore sizes of dredged soil decreased the structural compactness increased significantly due to the formation of more calcium silicate hydrate and other agglomerated flocculent gel materials from the further reaction between steel slag and cement hydration products. The results of this study can provide technological parameters for the re-utilization of dredged soil stabilized with cement and steel slag. Full article

(This article belongs to the Special Issue Seismic Design and Structures Analysis of Construction Materials)

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