Nonlinear Finite Element Analysis of Non-Structural Components Anchorage under Extreme Wind Loads

Author(s):  
Sálvio A. ALMEIDA Jr ◽  
Serhan Guner

<p>Steel anchors are widely used to fasten structures and non-structural components (NSC) to rooftop concrete slabs, especially in high-rise buildings. However, several NSC anchorage failures have been observed in the last decades upon the incidence of hurricanes, resulting in loss of service in essential buildings, detachment of the component, and water intrusion, all of which significantly delayed the recovery of the affected communities. From the observed failures, three main mechanisms were identified: steel rupture, concrete breakout, and bond failure. In this study, a three-dimensional nonlinear finite element methodology using a concrete damaged plasticity approach is developed to predict the response of steel anchors installed into a concrete slab. The methodology is verified with experimental results for each failure mechanism and subsequently used to study the effect of service-load concrete cracking and elevated temperatures – common conditions at rooftop level – on the response of the anchors. In addition, a first-of-its-kind multi-scale model of an NSC and its anchorage is created using the proposed methodology to investigate its behavior under dynamic hurricane load application. The findings suggest that these conditions can compromise the performance of NSC or promote its failure.</p>

Author(s):  
Ane de Boer ◽  
Max A. N. Hendriks ◽  
Eva O. L. Lantsoght

<p>The Dutch Ministry of Infrastructure and the Environment is concerned with the safety of existing infrastructure and expected re-analysis of a large number of bridges and viaducts. Nonlinear finite element analysis can provide a tool to assess safety; a more realistic estimation of the existing safety can be obtained.</p><p>Dutch Guidelines, based on scientific research, general consensus among peers, and a long-term experience with nonlinear analysis, allow for a reduction of model and user factors and improve the robustness of nonlinear finite element analyses.</p><p>The 2017 version of the guidelines can be used for the finite element analysis of basic concrete structural elements like beams, girders and slabs, reinforced or prestressed. Existing structures, like box-girder structures, culverts and bridge decks with prestressed girders in composite structures can be analysed.</p><p>The guidelines have been developed with a two-fold purpose. First, to advice analysts on nonlinear finite element analysis of reinforced and pre-stressed concrete structures. Second, to explain the choices made and to educate analysts, related to the responsibility of limiting model uncertainty.</p><p>This paper contains an overview of the latest version of the guideline and its latest validation extensions. Most important impact is the extended operational lifetime of an existing reinforced concrete slab structure.</p>


1993 ◽  
Vol 20 (4) ◽  
pp. 587-601 ◽  
Author(s):  
Pierre Léger ◽  
Patrick Paultre

Microcomputer finite element analysis of reinforced concrete slab systems can now be routinely performed to produce realistic numerical simulation of three-dimensional structural behaviour. However, an efficient use of this approach requires an automated integration of design and analysis procedures. Guidelines for proper finite element modelling of slab systems are first presented along with simple post-processing algorithms to perform automatically the design or verifications from the analytical results. Numerical applications on simple slab systems subjected to uniform and concentrated loads are then used to illustrate the relative performance between finite element analyses and the equivalent frame method. Key words: microcomputer, reinforced concrete slab, finite element method, structural design.


2017 ◽  
Vol 7 ◽  
pp. 267-272
Author(s):  
Beril Demir Karamanli ◽  
Hülya Kılıçoğlu ◽  
Armağan Fatih Karamanli

Aims The aim of this study was to evaluate the biomechanical effects on the craniofacial complex of skeletal anchorage and dental anchorage during face mask therapy. Subjects and Methods Two nonlinear finite element (FE) simulations were performed using a three-dimensional FE model. Face mask therapy with dental anchorage in the upper canines and face mask therapy with skeletal anchorage in the piriform apertures of the maxilla were simulated. In both simulations, the magnitude of the applied force was 750 g per side, and the force direction was 30° forward and downward relative to the occlusal plane. Results The circummaxillary sutures showed greater and more uniform stresses in the skeletal anchorage model than the dental anchorage model. This is the result of the more parallel forward movement of the maxilla in the skeletal anchorage model. Conclusions In Class III malocclusions with maxillary deficiency, for improved effects on the maxilla, choosing skeletal anchorage may be more effective in face mask therapies


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