To develop a durability plan for a girder bridge with a design life of $100$ years.

information:

Available on Canvas in Module "Bridge design project $-$ Spring $2024"$:

$"42907$ Design Project $-$ Bridge general details"

$"42907$ Design Project $-$ Bridge design tasks"

$"42907$ Design Project $-$ Preliminary detailings", providing a set of preliminary design drawings of the girder bridge reinforced$/$prestressed concrete members, comprising:

Reinforced concrete footings

Reinforced concrete columns

Reinforced concrete headstock beams

Reinforced concrete top$-$slab $($bridge deck$)$

Reinforced concrete barriers on bridge deck $($precast$)$

$"42907$ Design Project $-$ Design methods"

Mandatory concrete specifications for your project:

Minimum $28$ days characteristic compressive strength is $50$ MPa of all structural members.

Only GGBFS is available for this project as Supplementary Cementitious Material.

In general, to reduce the concrete embodied carbon, always use the maximum allowed GGBFS content in the binder composition in accordance with AS$5100\mathrm{.}5$ specifications. However, due to some limitations in GGBFS supply for this project, the maximum GGBFS content allowed is $50\%.$ Design method for the Service life report

Chloride exposure:

Design from first principle in exposure condition C$1$ and C$2$ does not allow any propagation phase of steel corrosion during the $100$ years design life.

Design from first principle in exposure condition B$2$: Propagation period is allowed within the $100$ years design life. Estimate the duration of both initiation phase and propagation phase.

The critical total chloride threshold used for the design $=0\mathrm{.}4\%$ of cement mass.

For members in tidal$/$splash zone and spray zone, use the Service Life Calculator based on CCAA values for Cs$,$ Da and alpha.

For members permanently submerged, also use the Service Life Calculator but with the Cs value determined for sea water chloride concentration $(0\mathrm{.}2\%$ by wt of concrete$).$

For members above spray zone $($in coastal exposure condition$),$ Cs value will be assumed equal to the one used for permanently submerged exposure condition.

Further assumptions:

All concrete member surfaces located on the top of the bridge deck $($top$-$slab and barriers$)$ are considered being in coastal exposure condition.

Concrete member surfaces below the bridge deck are considered being in spray zone, this includes headstock beams.

Carbonation

Design for carbonation$-$induced corrosion can include both initiation period and propagation period $($up to cracking$)$ making up the $100-$year service life.

Use the carbonation rates provided by the CBI Report $2005($lecture $4)$ for the initiation period ti$.$

If necessary, for the propagation period tp$,$ use the model and corrosion rates vs relative humidity provided in lecture $4,$ CD $=100$mm$.$

DEF

Design for acid$-$sulphate soil conditions for the design life of $100-$year based on AS$5100\mathrm{.}5$ specifications. Use solution which is appropriate with the construction method and means to avoid DEF in precast construction.

ASR

No ASR reactive aggregate are used in this project.