Hydraform Earthquake – Resistant System
Hydraform continuously endeavours to improve the structural performance of its interlocking masonry to widen its application area in over climatic & geological conditions. A large part of world falls under Seismic zones. Hydraform has run series of tests & validations to enhance its performance as earthquake-resistant system.
Wits University and Hydraform
In partnership with Wits University, Hydraform performed extensive seismic testing on seven structures, culminating in a final set of full simulated earthquake signals (chosen from well-known historical earthquakes: El Centro, Northridge and Llolleo) applied to the seventh structure. After the structures had been subjected to four such signals, run in sequence, negligible damage was evident.
Hydraform’s full-scale 4m x 4m shake table
As a result of this seismic testing, Hydraform now has a full-scale 4m x 4m shake table, of which the table design specification is:
- Show picture / movie clip of shake table
- 4m x 4m – Base structure size
- 20 ton 1DOF – Degree of freedom
- Test – Structure mass
- Horizontal movement ± 75mm – 150mm total displacement
- 1g – Acceleration (9,8m/ S²)
- Max velocity – 1000mm / sec for horizontal movement
- 2 actuators – Digitally controlled
- Freq range 0.1 – 40Hz
Report – Experimental Earthquake Loading of a Full Scale Dry Stacked Masonry Structure (written and produced for the web by Dr. A. Elvin and Dr. N. Elvin)
Earthquake simulations were conducted on a full scale, dry stacked, masonry structure made out of Hydraform bricks (Figure 1). Three earthquakes were considered: (a) the elCentro, (b) the North Ridge and (c) the Llolleo. The acceleration time histories (see Figure 2 below) from these three earthquakes were integrated, to produce displacement time histories, and then high pass filtered (see Figure 3). The filtering proved to be essential for two reasons: (a) to remove drift in the displacements, and (b) to facilitate the testing with the equipment available.
Gujarat State Disaster Management Authority (GSDMA) has, among others, also recommended Compressed Earth Blocks (CEB) & Compressed Earth Interlocking Blocks (CEIB) as appropriate for use in Earth Quake Resistant Structures and has issued comprehensive guidelines in this respect. For details, please refer to relevant GSDMA guidelines.
To address specific application, Hydarform India a modified interlocking Block to suit their vertical + horizontal reinforcement requirements in Earth Quake Resistant Housing Structures in Gujarat.
Hydraform achievements in India and Argentina
Hydraform’s Earthquake-Resistant Building System has been successful in the earthquake-stricken regions of India. In Argentina, the conventional Hydraform blocks were used in a reinforced concrete frame which tied the walls, foundation and roof together, providing seismic resistance. In India, a slightly modified Hydraform block allowed horizontal reinforcement at intermittent levels and vertical reinforcement at corners in case of load bearing structures or use in reinforced concrete frame.