PIR-project C - Bridges PIR (Project C) Sem 1 2019 PDF

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Bridges PIR (Project C) Sem 1 2019...

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PIR - Oxley Creek Bridge PROJECT C – REMOVABLE BRIDGE GRANT SAMPSON - 45799042

Executive summary In the Oxley creek catchment region, the Brisbane city council has set aside some funding for the development of the area to turn it into a world class greenery area for locals and tourists to enjoy. Part of this, is to implement a pedestrian/cycle bridge to connect the entire Oxley creek corridor, from Larapinta through to the Brisbane River. The bridge will need to accommodate for other users such us disabled wheelchair people and even horses. A problem that the area faces is that it is part of an overflow zone of the Brisbane river and could be subject to fast flowing flood waters. This problem means that the bridge should be moveable to allow flood water through so the bridge does not get damaged or destroyed. I propose the Idea of a draw bridge that will be mechanically lift. This bridge design will be the best to suit the problem as it is strong and sturdy and will be able to withhold unbearing forces and will also flow with the design to suit its environment. Overall, by developing this bridge over Oxley creek, it will finalise the spectacular environmental zone and ultimately create a world class tourist and local hotspot for everyone to enjoy. Table of Content

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1.0 Introduction.....................................................................................................................................3 1.1 Background..................................................................................................................................3 1.2 Aim of Project..............................................................................................................................3 2.0 Problem Definition...........................................................................................................................4 2.1 Design Constraints.......................................................................................................................4 2.2 Design Functions..........................................................................................................................4 2.3 Social Impacts..............................................................................................................................4 3.0 Project Scope...................................................................................................................................5 3.1 In/Out Scope................................................................................................................................5 3.2 Assumptions................................................................................................................................5 4.0 Literature Search..............................................................................................................................6 4.1 Bridge Background.......................................................................................................................6 4.2 Bridge types.................................................................................................................................6 4.3 Materials to use...........................................................................................................................8 5.0 Feasibility Calculations.....................................................................................................................9 5.1 Design Sketch...............................................................................................................................9 5.1.1 Side View..............................................................................................................................9 5.1.2 Front View.............................................................................................................................9 5.2 Bridge opening...........................................................................................................................10 6.0 Conclusions and Recommendations..............................................................................................11 6.1 Conclusion.................................................................................................................................11 6.2 Recommendations.........................................................................Error! Bookmark not defined. 7.0 Bibliography...................................................................................................................................12

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1.0 Introduction 1.1 Background The project that has been assigned to me and my team is to develop a pedestrian and cycle bridge that can accommodate other uses such as horse riders and wheelchairs. The bridge is to be implemented in the Oxley creek catchment region and is marked out on the map shown in figure 1 to the right. The reason for adding the bridge to cross the Oxley creek is to finish up one of the walking and cycle trails that pass the Oxley common area and connect the entire Oxley creek corridor, from Larapinta through to the Brisbane River (Document 3c, page1). The area is currently being developed

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into an outdoor community space to activities. There are different ‘zones’ in the com feature which is to be built, a pedest come and view a few of the 200 diffe

1.2 Aim of Project The aim of this project is to build a moveable bridge in the Oxley Creek catchment region. The bridge is to accommodate the needs and requirements of the locals and allow for different types of pedestrian traffic through, including; wheelchairs, horses, cyclists and foot traffic. The Oxley Creek area’s council, who is leading the project, have given specific guidelines of which the bridge should follow. A side objective is that the bridge is to be moveable in case of fast flowing flood waters that rise to ensure that it complies with the Master Plan flood preparedness and resilience strategy.

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2.0 Problem Definition 2.1 Design Constraints For the Brides to be built there are a few constraints that have been put in place by Oxley Creek PTY LTD that we must follow and obey. They have specifically requested that the dimensions of the bridge must be two meters in width to allow for potential horse riders to come through, this means that we will also have the bridge ‘split’ into two lanes to allow both directions of traffic to pass. The bridge must also have a head clearance of three meters. Another constraint we will have to follow is that the bridge must be wheel chair friendly, thus meaning the gradient of the bridge shall not exceed 1:20 (1-meter rise for every 20 meters run). The overall length of the bridge must span twenty meters across the creek and clear the average water level by 1.8 meters.

2.2 Design Functions The Function of the bridge is that it overall has to be a strong reliable bridge that can support pedestrians, cyclists and other traffic that may come through the area. The bridges main feature should be that it is able to move out of the way of rising flood waters to avoid being damaged. It must be able to clear a 16m by 5m gap when it is opened. Due to the thriving bird life in the Oxley creek catchment area, the council has said that we must implement a bird watching tower on the bridge to allow locals to view the birds from a purpose-built platform.

2.3 Social Impacts Many groups will have a say in the project and different groups will be affected in diverse ways. We will take into consideration each one of the steak holders in the respectively diverse ways and hold a meeting to gather their thoughts. Some steak holders include: -

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Land owners Residents Workers Local Business owners Community Groups o Bird watching society o Elderly homes o School Groups o Environment Groups Oxley Creek Transformation PTY LTD Future Visitors

Each one of these groups should have a say in the project so we can take into consideration all of their needs. We will speak with the Bird Watching Society to find out how we can create the perfect mode to view the birds. e.g. Find out how high we should position a bird watching tower and where it should be. Elderly people may not be able to climb stairs so we will have to account for that with a ramp or potentially implement a lift system. All of the design stages will need to be checked by Oxley Creek Transformation PTY LTD as they are the ones running the project and employing my team.

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3.0 Project Scope 3.1 In/Out Scope In Scope

Out of Scope

The Bridge needs to be removeable and move out of the way of a 16x5 meter object.

Acidic soils in the area that may damage surrounding plant life should be treated by an environmental Engineer.

The bridge needs to support 3 tons of weight under full load and capacity.

Need to consider strong wind factors that may affect it or natural disasters such as bush fires.

The bridge should have safety railings along the bridge edge.

The builders may construct the bridge with bad build quality as they could skip steps and take shortcuts.

The bridge design needs to be visually appealing and consider the area’s history and heritage.

The bridge may require future improvements and renovations to keep it in a good useable condition.

The bridge must be of certain dimensions. 20 meters long, minimum of 2 meters wide with a height of 3-meter head clearance.

We don’t have to know how to operate the industrial equipment to build the bridge.

The mechanism on how the moveable part of the bridge will function.

How the materials get transported to the build site of the bridge.

The total weight of the bridge and the environmental impact it has on the area.

The price of the bridge and how much it will cost the council (need a surveyor to estimate).

3.2 Assumptions For the project, we must make a few assumptions before we start. Assumptions - Unlimited funds to build the bridge -

Any material is allowed to be used

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The bridge won’t need future maintenance

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Effects - An overpriced design for the solution that may over complicate the real solution. - May affect the overall price of the bridge and could also over engineer it by using stronger materials that may cost more. - As the bridge will have moving parts, without maintenance they will degrade and might not be usable due to safety or operational reasons.

4.0 Literature Search 4.1 Bridge Background There are multiple types of bridge structures that have been created for many different types of reasons. Bridges have been used to span across obstacles such as valleys, water ways and obscure objects to allow for an easier and safer passage [ CITATION His19 \l 3081 ]. The purpose and need of the bridge will largely define what type of bridge is to be used. Each structure has its pros and cons to each scenario. If we look back in history, we can see some critical errors that have occurred when a bridge was chosen. The most famous incident was the Tacoma narrows bridge when it collapsed in 1940. This bridge was a suspension bridge that spanned across the Tacoma Narrows straight. The bridge collapsed due to the resonating airflow that passes through the area and was not calculated for when engineering the bridge[ CITATION Mer15 \l 3081 ]. This is just one example of where a small factor may be ignored and can lead to a big disaster.

4.2 Bridge types As stated in the project introduction the goal of this bridge is to span 20 meters but to also be moveable in case of a flood and should move 5 meters above the average normal waterline. Below is a comparison of different moveable bridge types that have been use through out time.

Vertical Lift Bridge The vertical lift bridge is one of the most vastly used moveable bridge types that has been constructed and uses elements from different bridge types to support its load, being a beam bridge that essentially is lifted vertically to move out of the way. [ CITATION The18 \l 3081 ] Pros Cons - The bridge design is simple - Has a limit to what size object can pass - Strong and sturdy as everything is fixed through when opened fully. together. - The design could be very heavy if - Doesn’t not rely on any other forces to counterweights are used. keep it upright and stable. - It requires more materials to construct.

Bascule Bridge The bascule bridge or better known as the draw bridge is one of the oldest forms of a moveable bridge and is most know for its use in the medieval times. The bridge relies on it being pulled from a horizontal position to a vertical stand point. [ CITATION The18 \l 3081 ][ CITATION Cor19 \l 3081 ] Pros Cons - The bridge is strong yet simply designed - The bridge is not fully connected to the - Can allow any sized object to pass. ground or an anchor point it the middle through as there is no vertical max height and possess a weak point for a critical limit. failure. - The resources needed are very minimal - Requires a strong motor or pulley system and requires little materials. to function effectively and lift the bridge.

Submersible Bridge A submersible bridge does essentially what it is called and will submerse itself below the water line. This bridge type may not be the most widely used bridge but in certain applications it lends itself very well. [ CITATION The18 \l 3081 ] Pros Cons - Can allow any sized object to pass through - Depending on the water depth, create as there is no vertical max height limit. shallower water for boats to pass. - The resources needed are very minimal - If fast flood water comes, the drag it may and requires little materials. create when submerged might allow it to

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be pushed out of position and break.

Vertical lift Bridge The vertical lift bridge is one of the most vastly used moveable bridge types that has been constructed and uses elements from different bridge types to support its load, being a beam bridge that essentially is lifted vertically to move out of the way [ CITATION The18 \l 3081 ]. The way that this Bridge lifts itself is through a few different methods and can change for different applications. One of the ways is through a counter weight mechanism that will drop the weight down the tower to the bridge. The second way the bridge can be lifted is using a pulley block system attached to a winch at the bottom. By using pulley block, the force needed to pull the bridge to the top can drastically decreased. [ CITATION ETC17 \l 3081 ]

Figure lift 2 and 3 [ CITATION a \l 3081 ] The18 be

Bascule or Draw Bridge The bascule bridge or better known as the draw bridge is one of the oldest forms of a moveable bridge and is most known for its use in the medieval times. The bridge relies on it being pulled from a horizontal position to a vertical stand point [ CITATION The18 \l 3081 ]. A traditional draw bridge utilizes a cable to pull the bridge up Figure 4 and 5 vertically compare to a modern bascule bridge with uses strong pistons and counterweights to push the bridge up. There are also [ CITATION The18 \l two different forms the bridge can come, a single and double leaf 3081 ] bascule, which is exactly what it says it is. The single leaf has one part that moves that also spans across the entire distance where as the double leaf will span halfway with both sides being able to be opened.[ CITATION Enc19 \l 3081 ]

Submersible Bridge A submersible bridge does essentially what it is called and will submerse itself below the water line. This bridge type may not the most widely used bridge but in certain applications it lends itself very well. Small boat passages with little car traffic to pass the bridge would suit its needs [ CITATION The18 \l 3081 ]. There are many types of submersible bridges that may be a combination of multiple disciplines. One type is a floating bridge type that is filled and emptied with water to allow it to either sink or float. This type of bridge utilizes hydraulics and will pump a large amount of water in and out. For example, the fundamentals say that if your bridge is to hold two tons of weight, it must displace two thousand litres of air and water, depending on the bridges position. Another submersible bridge type is a inversed bascule bridge that will fold downwards into the water instead of vertically upwards. [ CITATION Col19 \l 3081 ]

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be Figure 6 and 7 on [ CITATION Col19 \l 3081 ]

4.3 Materials to use Different materials will be used for different bridges depending on their usage and purpose. Common materials used is things such as wood, steel, aluminium, plastic and concrete. The location of the bridge plays a large role in the choice of material and how it is treated. If the bridge is in a low lying, damp and humid place such as a marshland, building it out of wood may not be entirely the best choice as it is prone to become weak and flexible from the water, unless properly treated. Likewise, if your bridge is positioned near sea water, ideally using bare steal is not great as it is highly prone to becoming easily rusted unless it is properly covered and treated with a special paint.[ CITATION Puu18 \l 3081 ] Each material also has its own strength and tensile strains it can hold. Each material has a certain point at which it will break under a certain force and each material has its own forces it will react well with, such as compression and tension forcers. The below table shows the facts and figures associated to each material [ CITATION HyT19 \l 3081 ]: Material Steel

Facts and Figures. - Most commonly used material for bridges dues to its strength vs weight ratio - Has a tensile strength of 250 MPa - Can expand and flex when heated and may distort the shape - It will bend and flex before snapping or breaking - Can be an expensive resource to use - Susceptible to rust when left in elements Wood - Very basic material that has been used for centuries - Cheap resource to build with as its very common - Susceptible to damage and wear and tear the most as water can affect it the most. - Considered a light material to use compared to others. Plastic - Very light weight material - Synthetic and man made through processing many different materials - Weak material to use and very malleable - A mediumly priced material to use - More commonly used for non-load bearing tasks due to its strength Concrete - The most commonly used material due to its availability and cheaper price - Becomes a lot stronger when reinforced with steel bars through it - Very heavy material but strong Aluminium - Durable material and light weight - Has a tensile strength of 520MPa - Does not rust as it does not contain steel - Fairly expensive material to build from as It has to got through a special process to create straight aluminium that we can use All Images used were sourced from shutter stock ClipArt. [ CITATION Shu19 \l 3081 ][ CITATION

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Puu18 \l 3081 ]

5.0 Feasibility Calculations The calculations for the bridge have been based on estimates and average results found. The following references were used through ought the calculation process. [ CITATION Sci \l 3081 ] [ CITATION Sci17 \l 3081 ] [ CITATION Puu18 \l 3081 ] [ CITATION HyT19 \l 3081 ]

5.1 Design Sketch 5.1.1 Side View

5.1.2 Front View

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5.2 Bridge opening The bridge will be opened vertically via a draw string and will using a pulley system controlled by a winch to open the bridge. The design specifications that have been set out, is that the bridge must be able to open to allow a 16-meter-wide object that is 5 meters tall to pass through. To do this we have calculated the minimum angle that the bridge must open to allow this, whilst saving energy and time.

Therefore, we will round the an...