Red House Building
 

Million-dollar restoration

Celtest’s specialist expertise vital for Red House

Parliament project in Trinidad and Tobago  

 

Client

The iconic Red House in Port of Spain was built in 1844, and is the seat of parliament in the Republic of Trinidad and Tobago.

In 1903, fire destroyed parts of the original building, including the roof, wooden floors and windows.

By 1907, the building was redesigned by public draughtsman Daniel Hahn, adding the Rotunda (the high central cupola), the ornate stucco ceilings in the southern and northern chambers, and the parapet around the roof.

However, serious structural problems caused Parliament to abandon the building in the early 1990’s. Restoration started in 1997, and continued for the next 20 years, costing over a hundred million pounds.

In 2017/18 structural strengthening works was undertaken by Celtest on behalf of Tohmatsu Technologies of T&T, using a Cintec anchoring system.

 

 

Challenge

For years, Cintec North America worked with the main contractor and designers on The Red House’s structural requirements. The work included major strengthening of the building using anchors up to 36.5m long.

In 2017 Tohmatsu Technologies of T & T secured the structural anchor contract; however, the necessary technical skills were not available in the Republic of Trinidad and Tobago to drill and install the anchors.

Celtest who are an approved Cintec installer and experienced in international work were contacted by Tohmatsu Technologies and subsequently, were awarded the contract to install the Cintec Reinforcement System.

Shortly after being awarded the contract, Jason Chinery site services manager, and drilling supervisor Neil Aindow, flew out for a site visit to assess the job and try to foresee potential issues. The first one noted was the heat and humidity – a little different to Wales, and while lovely when sat by a pool, the heat was not so nice for a full day's work.

 
 
Celtest Anchor Installation
Celtest Anchor Installation
 
 

Major challenges included the installation of multi-length anchors to strengthen the building, which was constructed from nonreinforced concrete from the late 1800’s.The anchors ranged from 0.8m to 36.5m long, with the majority between 11-13m in length.

Eight of the 36.5m-long anchors were to be installed on the first floor of the building, with 2no anchors drilled horizontally side by side through a 550mm thick wall. Accuracy was critical, as misalignment by just one degree would result in the drill exiting the side of the beam before drilling half the hole.

In addition, the concrete walls that were cast over 100 years ago were not straight, necessitating trials for altering the direction of the core bit.

Trials were undertaken in Bangor using precast concrete units set up over a distance of 36.5m to replicate site conditions. The trial was required to assess the accuracy of the drilling over such a long distance and the feasibility of installing the longest Cintec anchor ever attempted. It was predicted the combination of gravity and the barrel weight would pull down the core barrel over the 36.5m length. Trials proved that deliberately pointing the drill up by 0.5 degrees would cancel that effect.Pockets were cut out at the side of the concrete at regular intervals to expose the core barrel and re-adjust direction if necessary. This procedure was also possible on site.

The trial was a success as the drill exited at the opposite 36.5m end of the concrete exactly as predicted vertically and only 50mm out on the horizontal. The 36.5m long modular anchor was also installed and grout pumped into a fabric ‘sock’ which is fitted overthe entire length of the anchor. The sock expands with the grout to fill the drilled holes entirely and prevent any grout loss in voids.

The drilling and grouting equipment was shipped over to Trinidad in early September 2017 via sea freight, with smaller items going via airfreight.

 
 
Celtest Drilling
 
 

Neil Aindow, Mark Bullock and Kieran Williams initially worked in Trinidad from September-December 2017. When they returned in January 2018 to complete the job, they were accompanied by Nick Owen and Jamie Aindow. Dion Parry also flew out at Easter time for a few weeks to provide cover.

At The Red House, holes ranging from 40-100mm diameter were drilled in the concrete, and the Cintec anchors and grout ‘sock’ placed in position, which involved assembling the anchors in the hole as they were too long to ship complete or to get into position inside the building. After insertion, synthetic grout was pumped into the ‘sock’ to provide a permanent cementitious anchoring solution.

The grout was mixed in containers placed in ice buckets, and the water from the buckets was also used to mix the grout to ensure the grout didn’t set before the ‘sock’ was filled.

The temperature of the grout and water was monitored throughout the installation process.

The 8No 36.5m-long anchors were all completed successfully and every hole exited at the small target area within acceptable tolerances.

 

 

Conclusion

The 36.5m anchor is the longest Cintec anchor ever installed. Previously, a 34m anchor was used in Christchurch, New Zealand, installed by Cintec.

Celtest built an effective working relationship with the teams from Tohmatsu Technologies of T&T, which enabled efficient use of resources, assurance of safety processes, swift resolution of problems and completion of projections on time.

After the work on site was completed, Tohmatsu sent its site-based staff and the Celtest operatives to Tobago for a weekend on the beach as a thank you for the completion of a successful project.

Celtest is uniquely placed in the industry with its range of UKAS accredited testing and anchor installation and drilling abilities to provide project resources and testing for projects worldwide.