Structural Analysis & Design of Tall Structures

Tall buildings pose unique challenges in the design and Construction. Tall buildings are generally flexible with the time period of vibration in the range of a few seconds and therefore have to be designed for special wind effects like Gust and across wind oscillation due to vortex shedding.

The lateral drift has to be controlled to maintain occupant comfort by provision of shear walls and RC core. Engineering Halls I to V, SGTF, Stacks, Overhead water tanks, are some of tall structures in RCC designed and constructed by CEG. Apart from RCC structures, tall pre-engineered steel structures such as PPRD & MSTF, lab buildings like PRPD, DWR, EID-RTSD, ITSTF and AUSC are also designed and constructed by A&SED.

Analytical model of Exhaust fan building (left) and DFRP Zone-VI building (right)

For analysis and design of Civil Engineering Structures including Nuclear Safety related Structures, a host of computer programs and tools have been developed for various applications such as:

• Missing mass correction tool for response spectrum analysis.
• Development of Floor response spectra in FE model for the qualification of equipment
• Simulation of soil structure interaction
• Limit state concrete design of beam, columns, footings as per Indian/ AERB/ ACI standards
• Design of arbitrary shaped column sections for biaxial bending
• Analysis and Design of Embedded plate and anchorage in concrete for supporting equipment

• Computer program for CDFM based seismic margin assessment for finding HCLPF factor of safety related buildings
• Moment curvature and hinge definitions for non-linear static pushover analysis for SMA
• Computer program for Seismic re-evaluation of safety related R.C structures

Testing quality of concrete making materials like Cement, Aggregates, Water, Admixtures, etc., Drinking water, Construction water and sewage water testing for various DAE constituents in Kalpakkam.

Designing of Concrete mix proportions and field control of concreting (mass concrete heavy density concrete, high performance concrete etc.), road works for IGCAR, and other DAE constituents at Kalpakkam.

Structural health assessment of reinforced concrete buildings is part of ageing management. The goal of ageing management is to address systematically all the time-dependent parameters that can jeopardize the safety of the building during its life.

Concrete is a durable material, however, experience shows that ageing degradation of concrete structures, often caused or accelerated by factors such as faulty design, use of unsuitable or poor quality materials, improper Construction.exposure to aggressive environments, excessive structural loads and accident conditions, can impair the safety functions of concrete structures and can increase risks to public health and safety.

Effective ageing management of concrete structures is required to ensure their fitness for service. Concrete Laboratory team inspects buidlings to assess for spalling, cracking and depletion of concrete membres and brick masonrythrough visual examination and further conducts necessary Non Destructive Testing and ascertain soundness of embeddded reinforcement by conducting relevant field & laboratory tests and takes up necessary repair if necessary following national and international standards.

An alternate concrete based on industrial waste products have been developed to replace conventional lime stone concrete used as a sacrificial layer in FBR. Cube specimen were cast and tested in hot sodium at MINA facilities of SED- SQRMG. Initial studies of hot sodium interaction with GPC gave better results.

Hence, Ten different mixes with varying proportions of fly ash and GGBS were developed and tested in Hot sodium. The results are analyzed and optimum mix identified (3 Nos. considering strength parameters) for further characterization such as abrasion resistance.