Vibrational Response of Structures Exposed to Human-Induced Loads

Knudsen, Jonas Syders; Grathwol, Nikolaj; Hansen, Stinus

doi:10.1007/978-3-319-74421-6_20

Cited by 3 publications

(2 citation statements)

References 1 publication

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“…Certainly, the ISO method is simple and efficient for design practice. On the other hand, research studies highlighted that the approach (and other criteria in which the vibration thresholds are provided as a function of the structural frequency only) can have intrinsic limits when applied to pedestrian systems with reduced mass ( [56,57], etc. ), like the walkway herein explored and glass structures in general.…”

Section: Appl Sci 2019 9 X For Peer Review 13 Of 26mentioning

confidence: 99%

Reliability of Field Experiments, Analytical Methods and Pedestrian’s Perception Scales for the Vibration Serviceability Assessment of an In-Service Glass Walkway

Bedon

Fasan

2019

Applied Sciences

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The vibration performance of pedestrian structures attracts the attention of several studies, especially with respect to unfavorable operational conditions or possible damage scenarios. Given a pedestrian system, specific vibration comfort levels must be satisfied in addition to basic safety requirements, depending on the class of use, the structural typology and the materials. To this aim, guideline documents of the literature offer simplified single-degree-of-freedom (SDOF) approaches to estimate the maximum expected vibrations and to verify the required comfort limits. Most of these documents, however, are specifically calibrated for specific scenarios/structural typologies. Dedicated methods of design and analysis, in this regard, may be required for structural glass pedestrian systems, due to their intrinsic features (small thickness-to-size ratios, high flexibility, type and number of supports, live-to-dead load ratios, use of materials that are susceptible to mechanical degradation with time/temperature/humidity, etc.). Careful consideration could be then needed not only at the design stage, but also during the service life of a given glass walkway. In this paper, the dynamic performance of an in-service glass walkway is taken into account and explored via field vibration experiments. A set of walking configurations of technical interest is considered, involving 20 volunteers and several movement features. The vibration comfort of the structure is then assessed based on experimental estimates and existing guideline documents. The intrinsic uncertainties and limits of simplified approaches of literature are discussed, with respect to the performance of the examined glass walkway. In conclusion, the test predictions are also used to derive “perception index” data and scales that could support a reliable vibration comfort assessment of in-service pedestrian glass structures.

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Section: Appl Sci 2019 9 X For Peer Review 13 Of 26mentioning

confidence: 99%

Reliability of Field Experiments, Analytical Methods and Pedestrian’s Perception Scales for the Vibration Serviceability Assessment of an In-Service Glass Walkway

Bedon

Fasan

2019

Applied Sciences

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“…It is planned to ensure vibrations comfort induced by rhythmic person loads by calculating the limit acceleration values based on the method defined in [112]. These values will then be compared against the requirements defined in EC1 [113] instead of using a minimum eigenfrequency threshold value.…”

Section: Short-term Goalsmentioning

confidence: 99%

Conceptual Design Tool for Structural Layout Optimization in the Early Design Phase

Rahbek

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This thesis develops a conceptual design tool capable of generating optimized structural layout suggestions for building design in the early design phase. The structural layout of a building is the arrangement and design of the load-bearing elements that support the weight of the building and resist external forces. The structural layout in this project solely consists of prefabricated reinforced (RC) elements. The use of prefabricated RC elements is embedded in the Danish construction industry and will likely remain so in the foreseeable future. Therefore, there is great potential for more effective use of concrete in terms of sustainability and decreasing cost. The proposed design tool can help fulfill this potential. Action Research (AR) is used to create the conceptual framework of the design tool. The AR analysis consists of semi-structured interviews and a co-creation workshop where architects, engineers, and contractors contribute to the development of the design tool to ensure that the final tool conforms to real-world practice. The final design tool is based on this framework and developed using four core principles: optimization, interactivity, dissemination, and automation. A novel parametric modeling method is developed in the design tool called Adjacent Polygon (APoly) representation. The APoly method creates a dynamic parametric representation of a given building plan to generate diverse yet feasible structural layout suggestions. The evaluation modules of different structural typologies are constructed using surrogate models in the form of Neural Networks. The surrogate models are combined in a hierarchical structure to create an algorithm capable of predicting the optimized geometry and corresponding cost for a structural element based on the external conditions inputted into the algorithm. The entire network of prediction models is then combined with a meta-heuristic optimization algorithm in the form of a Genetic Algorithm (GA) to create a surrogate-assisted optimization framework. A repair algorithm is incorporated into the GA to increase the number of valid solutions generated during each optimization iteration to decrease the convergence time. The performance and reliability of the design tool are validated through two groups of local and global case studies. The first group consists of parameter sensitivity studies on the local approximation modules for each structural typology. The second group of validation studies examines the design tool’s effectiveness across relevant building plans and scenarios. The corresponding results demonstrate that the tool can effectively adapt to these different settings and produce optimized structural layout suggestions. It is also demonstrated that the design tool can conduct multi-objective optimization and produce a front of Pareto optimal solutions.

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Pedestrian bridges structure; assessment of comfort and impact of human-induced vibration

Gaawan

El-Robaa

2019

BRS

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Vibrational Response of Structures Exposed to Human-Induced Loads

Cited by 3 publications

References 1 publication

Reliability of Field Experiments, Analytical Methods and Pedestrian’s Perception Scales for the Vibration Serviceability Assessment of an In-Service Glass Walkway

Reliability of Field Experiments, Analytical Methods and Pedestrian’s Perception Scales for the Vibration Serviceability Assessment of an In-Service Glass Walkway

Conceptual Design Tool for Structural Layout Optimization in the Early Design Phase

Pedestrian bridges structure; assessment of comfort and impact of human-induced vibration

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