We are currently carrying out a structural inspection and repair to a brick built railway bridge in North London.
Our client expressed concerns over the visible cracking and bowing present to the structure of which carries high speed trains into central London so it was vital that we acted quickly in order to carryout the inspection, design and implement a suitable structural repair scheme.
Bridge-reinforcement
To save time and cost in scaffold we opted to use our van mounted cherry picker that will enable our installation to be carried out rapidly, in less time that it would take to erect scaffolding.
The spandrel is suffering from de-lamination causing in some brickwork to fall from the masonry arch severely weakening the structure. the sofit which carries and distributes the loads of the masonry arch was showing signs of racking caused by vibration allowing water to penetrate into the structure causing defective pointing. the brick pier was also suffering from major cracking and separation.
We will be installing Twistfix helical beams at 300mm centres horizontally accross the masonry arch creating a grid pattern with the bars drilled 1.5m into the supporting pillars providing a reinforced structure distributing the loads. and over 4000 1.5m grout ties will be installed through the sofit into the arch pinning the sofit and preventing further delamination.
the works will be carried out so that the bridge remains fully functional and the road remains open and accessible.
At Newman’s we utilise modern methods of masonry repair to restore bowing walls and lintel failure to name but a few structural defects.
Our specialist services were called upon by a building surveyor managing the refurbishment of a Victorian built 1890’s semi detached house in Croydon, South London.
Bowing Building London
After completing our survey it was discovered that there was extensive outward movement to the front and gable elevations and with the loft conversion in progress the additional stress to the masonry was sure to cause severe movement.
Bed Joint Reinforcement
Over 30 Lateral restraint ties were used on the gable elevation alone into the first floor and the new loft floor to restrain the outward movement combined with bed joint reinforcement ensuring there would be no further outward movement.
Lateral Restraint Ties Installed
With the bed joint reinforcement being installed front the front elevation wrapped around the gable and into the rear elevation the lintel failure was repaired and the bowing restrained.
That phrase is commonly heard within the Newman’s office, being a common problem to Victorian and Edwardian built properties we are able to offer modern methods of structural repair to prevent and restrain outward movement.
Bowing House in Need of Restraint
Bowing walls are caused by a lack of lateral restraint, which allows the masonry panels to move independently often outwards severely weakening the structural integrity of the property.
This is often evident at the levels of the masonry where the floor joists run in accordance to the floor and ceiling joists. Tying into the floor and ceiling joists is essential in repairing and restraining the movement and traditional tie bars which are visible on many period properties are no longer required.
Lateral Restraint Ties
Newman’s utilise the Twistfix Heliforce system providing lateral restraint by inserting 1.0m, 1.5m or 2.0m ties into the floor and ceiling joists with a resin fix into the brick work providing an almost invisible repair once aesthetic brick repairs have been carried out. Incorporating lateral restraint ties with helical bar creating deep masonry beams and replacement wall ties remove the need for expensive intrusive and dangerous remove and rebuild techniques that may have been previously used.
Author: Jon Newman
Posted:
Categories: Bowing Walls
