Page 5 - A4 Post tensioning bar 1030

Macalloy Post Tensioning System

Working Load Factors gives recommended load factors achieved by the 1030 bars, with
for permanent and temporary typical results below 3.0%.
applications.
The working load factor to be used
in a design is at the discretion of Anchorage strength – anchorage
the Engineer but will normally be Properties efficiency tests in accordance with
that specified in the appropriate the requirements of ETAG 013 are
Standard. Extensive data and test reports carried out to verify that the failing
on bars and components are load in the anchorage is not less
For prestressed concrete available from Macalloy’s Technical than 95% of the actual failing load
construction, the current standard Department. in the parent bar or 95% of the
for buildings is BS8110 and for specified characteristic failure load.
bridges BS5400, which suggest The main properties of the 1030 Anchorage testing also verifies
an initial prestressing force of 70% bars are summarised as follows: that the ultimate failure occurs in
of the characteristic failing load. the bar and is not influenced by the
For ties and similar applications in Fatigue – threaded assemblies anchorage or coupler.
structural steel construction, the have a fatigue resistance in
requirements of BS5950: Parts 1 excess of two million cycles of Stress Corrosion – Macalloy
and 2 apply. loading over a tensile stress range 1030 bars have been subjected to
of 590-670 N/mm , exceeding the F.I.P. standard stress corrosion
2
Maximum prestress forces in the requirements laid down in test. No bars failed during the
accordance with EN 1992-1- ETAG 013. 200 hour duration of the test and
1: 2004 Eurocode 2: Design of subsequent tensile tests to failure
concrete structures, are given in Relaxation – the requirement laid showed no significant reduction in
the Macalloy 1030 Post Tensioning down in BS4486 for the loss of the ultimate or 0.1% proof stresses.
System European Technical stress due to relaxation in a bar
document ETA-07/0046. loaded to 70% of its characteristic
failure load, after 1000 hours
Ground anchorage design is at room temperature, is 3.5% NOTE: ETAG 013 approvals are
dealt with in BS8081, which maximum. This is comfortably for 1030 system only not S1030.

Millenium Bridge, London
Architect - Fosters and Partners
Main Contractor - Monberg Thorsen and Sir Robert McAlpine
Engineer - Arups

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