Rajesh R. Rele, Ranjan Balmukund, S. Mitoulis, S. Bhattacharya
The conventional design philosophy of bridges allows damage in the pier through yielding. A fuse-like action is achieved if the bridge piers are designed to develop substantial inelastic deformations when subjected to earthquake excitations. Such a design can avoid collapse of the bridge but not damage. The damage is the plastic hinge formation formed at location of maximum moments and stresses that can lead to permanent lateral displacement which can impair traffic flow and cause time consuming repairs. Rocking can act as a form of isolation by means of foundation uplifting which act as a mechanical fuse, limiting the forces transferred to the base of the structure. In this context, this paper proposes a novel resilient controlled rocking bridge pier foundation, which uses elastomeric pads incorporated beneath the footing of the bridge piers and external restrainer in the form of shape memory alloy bar (SMA). The rocking mechanism is achieved by restricting the horizontal movement of footing by providing stoppers at all sides of footing. The pads are designed to remain elastic without allowing their shearing. The pier, the footing and the elastomeric pads are assumed to be supported on firm rigid concrete sub base resting on hard rock. By performing nonlinear dynamic time history analysis in the traffic direction of the bridge, the proposed pier with the novel resilient foundation is compared against a fixed-based pier and classical rocking pier (CC). The proposed pier rocking on elastomeric pads and external restrainer (CP+SMA) has good re-centering capability during earthquakes with negligible residual drift and footing uplift. In this new rocking isolation technique, the forces in the piers are also reduced and thus leading to reduced construction cost with enhanced post-earthquake serviceability.
{"title":"Rocking isolation of bridge pier using shape memory alloy","authors":"Rajesh R. Rele, Ranjan Balmukund, S. Mitoulis, S. Bhattacharya","doi":"10.3233/BRS-200174","DOIUrl":"https://doi.org/10.3233/BRS-200174","url":null,"abstract":"The conventional design philosophy of bridges allows damage in the pier through yielding. A fuse-like action is achieved if the bridge piers are designed to develop substantial inelastic deformations when subjected to earthquake excitations. Such a design can avoid collapse of the bridge but not damage. The damage is the plastic hinge formation formed at location of maximum moments and stresses that can lead to permanent lateral displacement which can impair traffic flow and cause time consuming repairs. Rocking can act as a form of isolation by means of foundation uplifting which act as a mechanical fuse, limiting the forces transferred to the base of the structure. In this context, this paper proposes a novel resilient controlled rocking bridge pier foundation, which uses elastomeric pads incorporated beneath the footing of the bridge piers and external restrainer in the form of shape memory alloy bar (SMA). The rocking mechanism is achieved by restricting the horizontal movement of footing by providing stoppers at all sides of footing. The pads are designed to remain elastic without allowing their shearing. The pier, the footing and the elastomeric pads are assumed to be supported on firm rigid concrete sub base resting on hard rock. By performing nonlinear dynamic time history analysis in the traffic direction of the bridge, the proposed pier with the novel resilient foundation is compared against a fixed-based pier and classical rocking pier (CC). The proposed pier rocking on elastomeric pads and external restrainer (CP+SMA) has good re-centering capability during earthquakes with negligible residual drift and footing uplift. In this new rocking isolation technique, the forces in the piers are also reduced and thus leading to reduced construction cost with enhanced post-earthquake serviceability.","PeriodicalId":43279,"journal":{"name":"Bridge Structures","volume":"16 1","pages":"85-103"},"PeriodicalIF":0.6,"publicationDate":"2021-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3233/BRS-200174","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41839680","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Mechanical properties of soil are function of many parameters. Moisture content is one of the key factors that impact the soil’s mechanical properties. Soil-pile interaction and pile displacement in bridges can, therefore, be impacted by the moisture content. In particular, pile displacement in Integral Abutment Bridges (IABs) due to daily and seasonal temperature variations is a problem that has been under investigation. IABs don’t have joint and as a result all the load and deformation in the slab is transferred to piles. If piles are deformed beyond their yield point, plastic deformation can occur. The objective of this study is to evaluate the moisture content effect on the interaction of pile and soil and the resulting pile displacement through computational modeling. An ANSYS Finite Element Model (FEM) is used to repeatedly change the moisture content of the soil and adjust the properties and compute the displacement in the piles. It is shown that increasing the moisture content decreases several key parameters such as bulk density, young’s modulus, cohesion and Poisson’s ratio. The simulation results indicate higher displacements of the piles as the moisture content increases. This behavior can be explained by decreased elastic modulus. As a result, soil behaves more flexible and allows more displacement of the pile.
{"title":"Effect of moisture on mechanical characteristic of soil and interaction of soil-pile in integral abutment bridges","authors":"J. Razmi","doi":"10.3233/BRS-200175","DOIUrl":"https://doi.org/10.3233/BRS-200175","url":null,"abstract":"Mechanical properties of soil are function of many parameters. Moisture content is one of the key factors that impact the soil’s mechanical properties. Soil-pile interaction and pile displacement in bridges can, therefore, be impacted by the moisture content. In particular, pile displacement in Integral Abutment Bridges (IABs) due to daily and seasonal temperature variations is a problem that has been under investigation. IABs don’t have joint and as a result all the load and deformation in the slab is transferred to piles. If piles are deformed beyond their yield point, plastic deformation can occur. The objective of this study is to evaluate the moisture content effect on the interaction of pile and soil and the resulting pile displacement through computational modeling. An ANSYS Finite Element Model (FEM) is used to repeatedly change the moisture content of the soil and adjust the properties and compute the displacement in the piles. It is shown that increasing the moisture content decreases several key parameters such as bulk density, young’s modulus, cohesion and Poisson’s ratio. The simulation results indicate higher displacements of the piles as the moisture content increases. This behavior can be explained by decreased elastic modulus. As a result, soil behaves more flexible and allows more displacement of the pile.","PeriodicalId":43279,"journal":{"name":"Bridge Structures","volume":"16 1","pages":"75-83"},"PeriodicalIF":0.6,"publicationDate":"2021-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3233/BRS-200175","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47733390","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Emran Alotaibi, N. Nassif, M. Alhalabi, H. Sebai, Samer M. Barakat
Bridge safety is one of the most critical concerns among civil engineering fields due to its high importance. The redundancy of bridges was heavily investigated in the literature; however, they were focused on twin girder redundancy cases. Additionally, literatures were scarce in studies that focused on the improvement that should be made to achieve redundancy systems in different AASHTO I-girder types. Thus, this study focused on assessing the additional required number of tendons for different AASHTO I-girder types and spacing between them to achieve the redundancy of I-girder bridges. The additional unbonded tendons are suggested to be added externally or internally. The parameters varied in this study are compressive strength of ultrahigh-performance concrete (UHPC), spacing between girders (i.e. number of girders) and type of girders. Leap Bridge Concrete software was used to simulate the required structural modes. After performing extensive numerical analyses following AASHTO LRFD guidelines, the results have shown that in case of the removal of external I-girder, the tendons in the nearest girder need to be nearly increased by 1.85 to 2.3 times compared to the original design, depending on spacing, compressive strength, and the number of girders. On the other hand, in the case of interior girder removal, the number of tendons in the nearest two girders need to be increased by 1.24 to 1.32 times the original design. The effect of compressive strength variation of the used UHPC was negligible compared to spacing and type of girder. It is worth mentioning that all simulations in this study were verified using CSI Bridge software.
{"title":"Numerical investigation on redundancy of bridges with AASHTO I-girders","authors":"Emran Alotaibi, N. Nassif, M. Alhalabi, H. Sebai, Samer M. Barakat","doi":"10.3233/BRS-210187","DOIUrl":"https://doi.org/10.3233/BRS-210187","url":null,"abstract":"Bridge safety is one of the most critical concerns among civil engineering fields due to its high importance. The redundancy of bridges was heavily investigated in the literature; however, they were focused on twin girder redundancy cases. Additionally, literatures were scarce in studies that focused on the improvement that should be made to achieve redundancy systems in different AASHTO I-girder types. Thus, this study focused on assessing the additional required number of tendons for different AASHTO I-girder types and spacing between them to achieve the redundancy of I-girder bridges. The additional unbonded tendons are suggested to be added externally or internally. The parameters varied in this study are compressive strength of ultrahigh-performance concrete (UHPC), spacing between girders (i.e. number of girders) and type of girders. Leap Bridge Concrete software was used to simulate the required structural modes. After performing extensive numerical analyses following AASHTO LRFD guidelines, the results have shown that in case of the removal of external I-girder, the tendons in the nearest girder need to be nearly increased by 1.85 to 2.3 times compared to the original design, depending on spacing, compressive strength, and the number of girders. On the other hand, in the case of interior girder removal, the number of tendons in the nearest two girders need to be increased by 1.24 to 1.32 times the original design. The effect of compressive strength variation of the used UHPC was negligible compared to spacing and type of girder. It is worth mentioning that all simulations in this study were verified using CSI Bridge software.","PeriodicalId":43279,"journal":{"name":"Bridge Structures","volume":"23 1","pages":"41-50"},"PeriodicalIF":0.6,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3233/BRS-210187","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69853978","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Fatigue performance of singular and modular press-brake-formed steel tub girders","authors":"K. Barth, G. Michaelson, Robert M. Tennant","doi":"10.3233/brs-200168","DOIUrl":"https://doi.org/10.3233/brs-200168","url":null,"abstract":"","PeriodicalId":43279,"journal":{"name":"Bridge Structures","volume":"16 1","pages":"3-13"},"PeriodicalIF":0.6,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3233/brs-200168","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69853120","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Investigating the effect of span-length and earthquake directivity on the response of multi-span continuous girder bridges isolated by friction bearings","authors":"A. Vatanshenas, M. S. Rohanimanesh","doi":"10.3233/brs-200169","DOIUrl":"https://doi.org/10.3233/brs-200169","url":null,"abstract":"","PeriodicalId":43279,"journal":{"name":"Bridge Structures","volume":"16 1","pages":"27-37"},"PeriodicalIF":0.6,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3233/brs-200169","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69853169","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Condition assessment of superstructure component of reinforced concrete bridges through visual inspection in the Assam, India","authors":"Joydeep Das, Arjun Sil","doi":"10.3233/brs-200171","DOIUrl":"https://doi.org/10.3233/brs-200171","url":null,"abstract":"","PeriodicalId":43279,"journal":{"name":"Bridge Structures","volume":"16 1","pages":"39-57"},"PeriodicalIF":0.6,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3233/brs-200171","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69853278","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Unprotected polymer fiber reinforced concrete deck as a wearing surface of a bridge: Pilot application","authors":"P. Bílý, J. Fládr, P. Ryjáček, V. Stančík","doi":"10.3233/brs-200170","DOIUrl":"https://doi.org/10.3233/brs-200170","url":null,"abstract":"","PeriodicalId":43279,"journal":{"name":"Bridge Structures","volume":"121 1","pages":"15-26"},"PeriodicalIF":0.6,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3233/brs-200170","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69853221","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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