| 1. |
- Persson, Peter, et al.
(författare)
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Strategy for predicting railway-induced vibrations in buildings
- 2016
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Ingår i: Proceedings of the INTER-NOISE 2016 - 45th International Congress and Exposition on Noise Control Engineering: Towards a Quieter Future. ; , s. 2098-2109
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Konferensbidrag (refereegranskat)abstract
- Urban densification is a way of accommodating population growth. Land adjacent to railways is used for constructing residences and other buildings, and new tramway systems are planned. Under these circumstances, nearby buildings will be exposed to vibrations and noise that may become a nuisance for the residents. It is necessary, even at an early stage of planning, to assess the extent of the vibrations and state requirements for the building in order to avoid costly changes at later stages. Ground vibration induced by railway traffic is studied in the paper. The aim is to develop a strategy for predicting vibrations in nearby buildings in an early stage of the building process. The strategy is based on that there is a fairly good knowledge of the properties of the ground and that some on-site vibration measurements are made. By combining these with finite-element analysis, the vibration level in typical buildings can be predicted. Design of building foundations and structural design can then be addressed. Field vibration measurements along railway tracks as well as at built-up areas have been carried out. Conclusions from the measurements and numerical simulations are discussed to establish a strategy for predicting railway-induced vibrations.
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| 2. |
- Andersen, Lars Vabbersgaard, et al.
(författare)
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Influence of foundation type and soil stratification on ground vibration - A parameter study
- 2016
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Ingår i: Proceedings of the INTER-NOISE 2016 - 45th International Congress and Exposition on Noise Control Engineering: Towards a Quieter Future. ; , s. 7613-7622
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Konferensbidrag (refereegranskat)abstract
- Vibration of machinery and construction work are major sources of noise and vibration pollution in the urban environment. The frequencies dominating the vibration, and the distances over which it spreads via the ground, depend on the source. However, soil stratification and foundation type have a significant influence. Thus, in order to achieve fair accuracy in the prediction of ground vibration caused by sources vibrating on a foundation, accurate models of the ground and foundation may be required. However, for assessment of vibration in the design phase, simple models may be preferred. The paper provides a parameter study regarding the influence of soil stratification and foundation type on the ground vibration at different distances away from the source. Especially, vibration levels caused by sources placed on surface footings and piles are compared, employing a three-dimensional numerical model. Piles of different length are included in order to analyze the differences that can be expected regarding shaft-bearing and end-bearing piles. The paper provides insight into the significance of modelling the correct foundation structure and soil stratification and discusses the differences related to vibration near a source and at longer distances away from the source. Based on this, guidelines for model simplifications are given.
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| 3. |
- Andersson, Linus, et al.
(författare)
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Reduced order modeling for the dynamic analysis of structures with nonlinear interfaces
- 2019
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Ingår i: COMPDYN 2019 - 7th International Conference on Computational Methods in Structural Dynamics and Earthquake Engineering, Proceedings. - 2623-3347. - 9786188284470 ; 2, s. 2395-2406
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Konferensbidrag (refereegranskat)abstract
- In the present paper, linear substructures with nonlinearities localized at their interfaces, such as the joints in a beam structure, are studied. By subdivision of the total structure into substructures, reduced subsystems are obtained by component mode synthesis. Nonlinear elements are introduced at supports or between substructures. A numerical example is presented where a beam subjected to blast loading is studied. The influence of the nonlinear behavior as well as the number of retained fixed-interface normal modes in the reduced subsystems are evaluated. The response is also compared to the response of equivalent single-degree-of-freedom systems, which are frequently employed in blast load design calculations. For the load cases studied, the displacement computed from an equivalent single-degree-of-freedom system correspond fairly well to the displacement given by a refined two-dimensional beam model, reduced by substructuring. In contrast, the shear force differs significantly due to that higher order modes are neglected in the single-degree-of-freedom system.
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| 4. |
- Malmborg, Jens, et al.
(författare)
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Prediction models of free-field vibrations from railway traffic
- 2017
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Ingår i: COMPDYN 2017 : 6 th ECCOMAS Thematic Conference on Computational Methods in Structural Dynamics and Earthquake Engineering - 6 th ECCOMAS Thematic Conference on Computational Methods in Structural Dynamics and Earthquake Engineering. - Athens : Institute of Structural Analysis and Antiseismic Research School of Civil Engineering National Technical University of Athens (NTUA) Greece. ; , s. 4810-4820
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Konferensbidrag (refereegranskat)abstract
- Many cities experience an increasing population leading to a need for urban densification. In these cities, unused land close to railways will have to be developed with new residential and office buildings. The infrastructural demand will also increase, resulting in heavily trafficked roads and railways close to w here people work and live. Annoyance from traffic-induced vibrations and noise is expected to be a growing issue. To predict the level of vibration and noise in buildings caused by railway and road traffic, calculation models are needed.In the present pa per, a simplified prediction model is briefly described. This prediction model is based on the assumption that the ground and railway embankment can be described in an axisymmetric model , to provide the transfer functions between the track and the free-field . In the paper, the error that arise by assuming axisymmetric response is studied by comparing the response in a three-dimensional finite-element model. Transfer functions at several positions in the free-field are compared
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| 5. |
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| 6. |
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| 7. |
- Persson, Peter, et al.
(författare)
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Numerical Study of Reduction in Vibrations Induced by Water-Pipe System
- 2015
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Ingår i: Dynamics of Civil Structures. ; 2, s. 407-419
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Bokkapitel (refereegranskat)abstract
- In certain buildings such as synchrotrons and large ground telescopes, strict requirements are stated regarding the vibration levels. Both external and internal vibration sources, for example traffic and indoor water pumps, can have an appreciable effect on the vibration levels in the buildings. The synchrotron research facility MAX IV, which is currently under construction in Sweden, serves as an example case for the analyses. In MAX IV, several water-pipe systems used for cooling purposes will be placed near vibration sensitive equipment. These systems will transmit vibrations, into structural parts of the facility, which could exceed the vibration requirements. Structural modifications of pipe systems are investigated here by means of the finite element method in order to reduce vibration levels in the building. The finite element model employed includes a water-pipe system, adjacent building parts and the underlying soil. The use of fluid-structure interaction is investigated as well as the use of component mode synthesis. This paper focuses on the numerical procedure used as well as the effects on transmitted vibrations by different placements of the pipe supports.
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| 8. |
- Persson, Peter, et al.
(författare)
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Numerical study on reducing building vibrations by foundation improvement
- 2016
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Ingår i: Engineering Structures. - : Elsevier BV. - 0141-0296. ; 124, s. 361-375
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Tidskriftsartikel (refereegranskat)abstract
- Vibration disturbances in buildings may stem from ambient sources, such as motorway traffic, or from internal sources such as people walking inside the building. Vibrations can exceed requirements for sensitive equipment or cause annoyance to humans and therefore the vibrations may need to be reduced. Vibrations from both external and internal sources can be reduced by modifying the properties of concrete slabs and of the soil underneath. Soil can be improved by being mixed with a binder material in order to increase its stiffness. In this study, parametric finite element analyses were conducted on the achieved vibration reduction on a slab on soil from improving the properties of a concrete slab on soil or of the soil underneath. The size, elastic modulus, and depth of the stabilised soil were found to markedly affect the level of reduction obtained. The soil stabilisation at a vibration-sensitive facility was used as an example case, where the developed finite element model was calibrated to green-field measurements carried out on-site. Frequency spectra of both road traffic loads and internal pedestrian loads were considered in the model. The calibrated finite element model predicted reductions of almost 60% for the road traffic and 80% for the pedestrian load.
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