Structural and geotechnical engineering

Structural and geotechnical engineering

- building structures, industrial structures, bridges
- geotechnics
- soil-structure interaction
- deep foundations
- seismic analysis
- earthquake engineering
- signal processing

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2D drawings and 3D modeling

2D drawings and 3D modeling

- 2D drawings
- 3D modeling
- wireframes
- surfaces
- solids
- rendering

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Software development

Software development

- Nonlin Quake - software for nonliner seismic static and dynamic analysis of structures
- Simul-DLT - software for a fast dynamic load test of piles
- R-DLT – software for collection, management, analysis and monitoring the data of dynamic load test of piles

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Deciding the Order of Interventions on the Structure of Reinforced Concrete (RC) Bridges

Folic R., Cosic M., Folic B.: Deciding the Order of Interventions on the Structure of Reinforced Concrete (RC) Bridges (presentation)

A multitude of existing bridges fail to meet the criteria of seismic resistance, as designed according to inadequate regulations, which eventually led to the reduction in their resistance. This practice requires interventions (rehabilitation or strengthening) conducted on their structure, which in turn requires developing methods of assessment of seismic performances of existing reinforced concrete (RC) girder bridges. Due to budget constrains it is impossible to strengthen all the bridges, so that a list of priorities is necessary to be drawn. The rank of a specific bridge in this list is stated by the importance of the road, age of the bridge, technical regulations according to which the bridge was designed and the condition of vital support elements. Ranking requires conducting multi-criteria optimization. This paper is focused on overpass, which is used to demonstrate the developed methodology.

Damping Models

Folic R., Cosic M., Folic B.: Damping Models (presentation)

This presentation shows the aspects of damping modelling in structural analysis through the systematization of damping types and flowcharts, depending on the type of analysis applied: linear and non-linear, static and dynamic. Damping has been systematized based on the way it was introduced into calculations, i.e. over material damping, link element damping and damping directly introduced into the analyses which are conducted in capacitive, time and frequency domains. In the process of creating numerical structural models, the type of damping and the way of its introduction into structural analysis can be very efficiently selected by applying the flow charts developed. By applying the developed flowcharts, alternative approaches to the introduction of damping into structural analysis can also be defined.

Soil-Pile-Pier Performance

Cosic M., Folic B., Folic R.: Soil-Pile-Pier Performance (presentation)

In the presentation is shown a discrete numerical solid pile model with a discontinuity and defects. Model included performance-based seismic evaluation of the soil-pile-bridge pier interaction. The pile discontinuity and defects are modelled by reducing the specific finite elements and elastic modulus of concrete. The wave-propagation response of the pile was analyzed based on a step-by-step numerical integration using the Hilber-Hughes-Taylor (HHT) method in time domain (THA). The response analysis is performed with an integration of individual reflectograms into a reflectogram surface, which is generated in a 3D cylindrical coordinate system. Non-linear response of the system is considered using the incremental-iterative Newton-Raphson`s method, while the stability analysis is performed according to the modified geometrical nonlinearity analysis of stability. Determination of critical load and effective length of the pile are performed based on numerical solution and using regression analysis of the power function. The procedure of the soil-pile-bridge pier performance evaluation is based on the incremental nonlinear dynamic analysis (INDA). The system’s input signal is treated through the generated artificial accelerograms, which were subsequently processed by soil layers and for the bedrock. Fragility curves were constructed based on solutions of the regression analysis and the probability theory of log-normal distribution, while the generation of reliability curves is based on a solution of vulnerability.