Application of Active Control System on the Seismic Response to Unreinforced Masonry Structure
Socio Jiwapatria (TU Delft - Civil Engineering & Geosciences)
Andrei Metrikine – Mentor
Apostolos Tsouvalas – Mentor
Paul Lagendijk – Mentor
Antonio Jarquin Laguna – Mentor
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Abstract
The increase of the human-induced seismicity in the Groningen has increased the interest of all stakeholders to ensure the structural safety of all residents in the affected area. While there are already many conventional structural strengthening methods that are proposed and being implemented in the affected area, the study of a new innovative strengthening method by using an active control system is attractive and intriguing. The current structural upgrading strategies mainly focus on improving the structural strength and stiffness of the load bearing elements. The active control, on the other hand, could provide an additional dissipative energy mechanism to any building by counteracting the damaging force by the control force produced by the actuators.
The effectiveness of the active control is assessed with multiple time history seismic events in the Groningen area to see the robustness of the control system against seismic excitations with various characteristics. Checking of the structural response with consideration of Significant Damage Limit State is conducted. The control goal is to prevent significant damage of the structure so that the cost of repair, demolishing, or even re-construction of new dwellings could be reduced or even prevented. The terraced house is modelled as a single residential unit by a 2D finite element model. Only the façade wall is analysed as the terraced house is vulnerable in the out-of-plane direction and in a direction parallel to the façade wall because the façade piers are considerably narrow.
The active control application is realized by putting a steel truss at each façade wall that is connected by pneumatic cylinder actuators. The control strategy follows the closed-loop control scheme where the control force is calculated based on the feedback of the structural response. The control force is calculated by the Linear Quadratic Regulator (LQR) algorithm. The structure needs to be represented into a state-space representation for the LQR algorithm to calculate the control force. The structural response is solved by the Newmark Beta numerical integration. The time delay effect is also taken into account to consider a more accurate representation of the actual system. Simplified soil-structure interaction cases are also studied to see the effect of the soil conditions towards the control performance. Eventually, the preliminary dimensioning of the steel truss and the pneumatic cylinders is conducted to see the practicability to provide a small scale and realizable control system.