Seismic Retrofit of URM Building

PYTHON MT - Wall-to-diaphragm connections
PYTHON C - Double-brick and veneer ties

The Structure

Constructed with practices of its era, this mid-1900‘s four-story URM building boasts timber floors and brick cavity external walls. Deep timber joists are supported by external brick walls and intermediate timber columns.

However, seismic detailing falls short of modern standards, necessitating additional connections to bolster structural integrity. Originally, brick cavity walls offered thermal and moisture insulation but prove inadequate during seismic events. Given its size and weight, the building is vulnerable to seismic accelerations, necessitating the addition of structural load paths to meet modern seismic requirements in earthquake-prone areas.

THE SOLUTION

python shear studs - New Concrete Shear Walls

Given the size and seismic vulnerability of the four-story URM structure, additional load paths were necessary to channel seismic forces to the foundations. To address this, new concrete shear walls were installed in several bays, spanning the building's full height.

Epoxy anchors historically were used to connect such new concrete shear walls to the existing masonry. However, through innovation by PYTHON Fixings, the Engineer opted for PYTHON MT mechanical anchors as concrete shear/tension studs.

This choice resulted in a remarkable 5x faster installation compared to traditional epoxy methods. The impact on both project timelines and labor costs was substantial, showcasing the efficiency and cost-effectiveness of this solution.

PYTHON MT Structural Connection - Wall-to-Diaphragm Connections

In original construction, lateral wall-to-diaphragm connections between flooring systems and URM walls were typically absent.

To enable the existing timber floor system to act as a structural diaphragms and laterally restrain the URM walls, the Engineer specified PYTHON MT anchors between the floor joists and URM walls.

This widely adopted solution offers several key benefits. As mechanical anchors, PYTHON MT connections are less susceptible to on-site workmanship issues, providing greater confidence in their performance and reducing the need for on-site testing by contractors.

Faster installation compared to traditional epoxy alternatives results in 66% cost reduction.

The unique length of PYTHON MT anchors allowed for integration of the external veneer into the connection, creating a single, robust wall-to-diaphragm connection that ensures reliable lateral restraint for both the URM wall and external veneer.

“The PYTHON MT Fixings are unbelievable...installation is significantly more time efficient”

James, Site Manager at Rucon Construction


PYTHON C - Cavity-Wall Ties

Historic brick cavity walls offer excellent thermal and moisture insulation but often exhibit two structural deficiencies under seismic loading:

  • Degradation of original wall ties.

  • Inadequate out-of-plane capacity due to flexibility.

To address this, the Engineer implemented a solution using PYTHON C semi-rigid cavity ties. These ties replaced original corroded ones and facilitated composite behavior between the wall and external veneer, increasing out-of-plane capacity 5x and doubling displacement capacity.

This technique eliminates the need for additional internal structure, reducing project costs and preserving floor area, thereby enhancing the property's ongoing commercial value.

The PYTHON Fixings range are purposely engineered for remedial and seismic retrofit applications. They are ultra quick to install with no use of epoxy, see how simple the PYTHON MT is to install here.

To discuss your next project, contact the PYTHON Fixings team at info@pythonfixings.com.au or call 1800 PYTHON.

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