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Ascendas ITPP(2)

February 2021
Ascendas render 1

2/5/2021

Ascendas International Techpark Pune - Engineering

ITPP Engineering Aspect

This article is contributed by Mr Rakesh Morudkar, Managing Director, RSM Facade Solutions

The project is no less an engineering feat as it is a design one.

The Facade Consultant - 

RSM Design Solutions, the brain child of Mr Rakesh Morudkar is a facade engineering firm with a gamut of designers, engineers and structural engineers with operations spanning the Indian subcontinent. 

In tune with their mission to provide sustainable performing cost effective building envelopes addressing latest developments in the façade technology, raising quality standards, setting new bench marks in the façade designing and engineering sphere, Mr Morudkar embarked upon the journey to make the architect's vision an engineering marvel.

The Engineering - 

The architects - DSP Architects and Associates came up with a novel  and  innovative concept of a functional design for Sun Shading – a specially engineered fin which is 500 mm wide and  20 mm  thick.

In order to turn this Concept to realty, RSM Design Solutions began to engineer the solution in line with their policy of zero/negligible deviation from design intent. Thus, designs, alternative  designs,  calculations , analysis, heat gain studies and heat dissipation calculations etc. were  done in ECO tech.

Considering the property’s long life span it was proposed to go for reputed and tested façade system complying with local and internal regulations and the performance requirements

The system used for this project is a gasket based split unitised system from Technal – GEODE EL with following advantages -

  • Three way adjustable bracketing to incorporate gasket based insulation.
  • Three Barrier System to ensure water tightness.
  • Thermal-break system enabling heat dissipation.

Having  studied the architect intent, the façade consultants -  RSM  Design Solutions, did a thorough thermal analysis, a standard practice for the system and the same was repeated with the add on Fin. It was conceptualised to install Fin at a distance from the façade line with help of specially designed brackets which  were placed strategically not to hinder Openable windows, ease of replacability of glass and at Stack Joints etc. The main function being no heat transmission from Fin to the system.

Further RSM proposed to use same Technal system without any modification at VRV location.  Mesh and glass line was kept the same and not staggered, thus eliminating  additional hardware, brackets and labour for installation and in turn the total Project Cost.

As the design of façade had a cantilever of 3 meters,  RSM  designed the system considering  the above and the relevant values were proposed.

The Façade also had another combination – At refuge area the termination of two corners was at 90 Degree where the façade needed to extend.  The details proposed by RSM were correctly replicated without any deviation by Technal – refer Figure  i

FIGURE I – REFUGE AREA CORNER DETAILS

 

The fins were designed considering ergonomics, aesthetics, functionality and repeatability and followed the below mentioned standars -

  • Design was done adhering  on IS  875 :  1987 PART( I ) -  1987 -  Dead  Loads.
  • Design was done adhering  on IS  875 :  1987 PART( II ) -   1987 - Imposed Loads.
  • The material Chosen Aluminium Extrusion  Profiles – Alloy Type – 6063 T 6 ( 63400 WP).
  • Design loading on System, to know the reaction load and its impact on the system was also carried out.
  • The system design was rechecked in terms of deflection criterion and non-fail safe values.
  • Centre to centre distance of the fixing bracket for Fin was optimised.

The ‘Counter Sunk bolt’ was also  designed to be flush with the fin surface and not jetting  out.

Manufacturing aspect:

The fin could be manufactured in two ways - Aluminium Sheet bending and Aluminium Profile Extrusions, both which pros and cons were weighed at length -

ALUMINIUM SHEET BENDING

Advantage

  • Easily available
  • Cost effective
  • Can be easily fabricated by skilled labour

Disadvantages

  • Improper Finish
  • Aesthetics will be hampered
  • Undulations likely to be observed on the Fin
  • Non uniform edge cure, likely to crack at a later stage owing to building movement, which may lead to water penetration over the years
  • Colour fading will also need to be dealt with.

ALUMINIUM  PROFILE EXTRUSION  :

Advantages:

  • Proper Finish
  • Edges maintain the structural stability
  • No variation in colour
  • Flexibility in terms of angle of horizontal and vertical elements of Fins at joinery

Disadvantage

  • Such size extrusion is not available in India and hence had to be sourced from abroad but it still worked out to be cost effective owing to the large volume and standardised sizes.

As the advantages of extruded fins outweighed those of fins made of sheet aluminium, Extruded profile fins were chosen.

Design and Engineering of Fins

Total number of fins for the Project is approximately 1800.

1. Design Consideration -

  • In depth analysis was done in order to arrive at the size of fin i.e. width, thickness taking into consideration the design load and safety factor.
  • The Height of the fin was decided based on the panel grid height and the location of openable windows.
  • Provision was also made to incorporate movement at expansion joints of the System at the stack head location to allow for the movement.

2. Ergonomics and Cost aspects -

  • The extrusion size was optimised and the wastage for the total fin was a meagre 2.5%.
  • The horizontal fin element was cut diagonally from the total extrusion to give better yield
  • The design also took into consideration the ease of joining and installation
  • The size of the Sheet - L 500 X W 20 X 3 MM.

 

Fin assembly and fixing

The horizontal Fin element was joined at 90 degrees to vertical part using corner cleat which was welded at the intersection. 

Fin fixing is detailed in following illustrations

Performance Mock-Up Test

A PMU test was carried out for the Technal system with the Fin  Element and it passed all the tests  successfully and with ease at the 1st go.

The test was carried out at Façade India Testing Laboratory, Murbad.

Further the Fin also Successful passed the Push and Pull test carried out separately after  , the PMU test.