RENAISSANCE

AT

SHORELANDS

                                 West Tower                                              East Tower

 

CASE STUDY

Project : Renaissance at Shorelands

Type of Project : High Rise Residential Building

Director in Charge: Anthony Farrell

Design Engineer : Kerrin Burgess

Design Team : Fullerton Diaz Architects (Architects)

                        C.E.P. Limited (Structural Engineers)

                        EDC (Mechanical/ Electrical engineers)

                        Bovis Lend Lease /Acuitas Caribbean Ltd (Project Managers)

                        Talma Mills Architects (Landscape)

Cost (TTD): $511 million

Project Description :

The Renaissance at Shorelands project comprised two twenty-two storey residential towers rising out of a three storey podiums. The first two levels are parking levels; level 3 amenities level with a central community pool, and the remaining tower floors residents with the roof of each accommodating two private pools for the penthouse apartments.

The project had been in development for two (2) years prior to C.E.P.’s appointment. However, the client decided to disengage the services of the then structural engineer. It was at this stage C.E.P. was asked to take the project to completion.

Our terms of reference was to redevelop the structural scheme, without making significant changes to the apartment layout as some were already pre-sold. The project was to be of steel construction with the steel being able to be erected independently of the concrete components. Finally, and most importantly designs of the major structural packages steel and foundations were to be completely ready for tender within a period of 3 months.

Challenges :

  • The designs period was very short and required an immediate design solution The structural geometry was complex and very difficult to model for analysis
  • The existing building geometry was very inefficient structurally as the elevator shafts were too smaller and very eccentric
  • Apartment layouts varied up the building and the outer envelope of the structure was offset inward every few floors. This coupled with an open car park at the first two levels below the towers, made it impossible to introduce new shear walls throughout the building’s height to stiffen the structure and reduce eccentricity.
  • The non-symmetric orientations of the towers on the podium resulted in a need for large quantities of transfer girders at the top of the podium as tower columns, if taken to grade level, would have resulted in obstructions at the parking levels.
  • The floor diaphragm was not completely wrapped around the stair core resulting in an inefficient transfer of floor loads to this main stabilizing element.
  • The proposed building was being constructed in a residential area, and as such noise and disturbance was to be kept to a minimum. This would have posed a challenge especially if driven piles were to be used as the foundation system.

Solutions :

  • C.E.P. employed the use of our technology to directly import the irregular structure’s geometry from the architects drawings to our design software, thus reducing modelling time required.
  • The structural systems employed was a dual system comprising of steel moment resisting frames coupled with braced frames in the stair shaft and a composite shear wall for the elevator core.  This arrangement allowed the steel to be erected ahead the concrete..
  • A dynamic analysis was performed to simulate earthquake loads and assess the structure response to these loads. Thus allowing a fairly accurate assessment of the irregular building’s behaviour in such events
  • A wind tunnel test was done to assess the structure’s response to wind loads as well as to determine cladding loads and pedestrian level wind effects
  • To reduce the impact of the tower columns on the parking levels, it was decided to remove some of the tower columns thereby opening up some of the span. Some slight adjustments to the column locations were also done. This action resulted in a reduction in the need for transfer girders, thereby reducing it from 10 to 3, resulting in overall cost savings and easier car park planning.
  • Composite  beam construction was used to optimize steel weights and produce cost savings
  • The lack of a diaphragm around the entire stair core resulted in inefficient use of this core. To correct this we made use of the steel deck pan of the stair itself, transforming it to a diaphragm, thus linking the entire core to the floor plate
  • To avoid noise during the construction of the foundation, drilled pile construction was used as the preferred foundation system. These large high capacity piles were substituted for the traditional smaller driven piles.  This system required fewer piles than driven piles and would have yielded a short construction time for the foundations, with less complaints from neighbours

Results :

Although a large number of constraints were imposed on C.E.P. for the designs of this structure, we were still able to deliver this structure on time and were also able to bring about a cost saving to the client. The structural inefficiencies were mitigated against and a workable structural solution obtained.