Expando Articles

Case Study At Liney Point

Difficult sites and issues with vibrations are now a thing of the past thanks to an innovative product that’s been tried and tested overseas now it’s finally come to Australia. Expando – a non explosive demolition agent, is suitable for difficult sites where vibrations and noise are an issue and those with a high concentration of rock or for confined spaces.

Expando, owned by a local Australian company, No Blast, is currently being used to excavate a site in Linley Point that will eventually become one of Sydney’s largest and most innovative homes. 

The development began with the demolition of two neighbouring waterfront homes that were situated on a steep precipice of rock descending to the waterline at the southern point of the bay. The terrain the houses were built on and the sheer size of the development meant the removal of a momentous amount of rock. Excavation has already been underway for nine weeks and there’s still another six weeks to go before it is cleared, leveled and ready for phase two. 

So with a project of this magnitude, where do you start? Stephen Johnson, owner of SJ Constructions, who has taken on the planning, design and development of the home, begins ‘For the first few weeks we went about the dig in the traditional way using an excavator but the noise and vibrations from the continuous thump of the excavator was affecting neighbouring properties so we stopped the dig and went about finding a less intrusive excavation method.’ 
 
‘When water freezes, it expands that’s why when water that collects in road cracks turns to ice in winter it enlarges those crevices into gaping potholes.’ I knew there had to be a man made solution out there that behaved in a similar way so I started a Google search and found a non explosive expansive mortar called ‘Expando’ from a local Australian supplier.’  

‘The owner of Expando, John Rothwell delivered the first load and demonstrated how to use it. It’s idiot proof really, easy to mix, non toxic so there’s no license requirement for careful handling and no OH&S issues.’ 

‘Because of the enormous scale of the project we wanted to make sure we had the best and most cost effective technique before we commenced, so we began experimenting with the size and spacing of the holes before we were satisfied we had the best method down pat.’
 
‘We start by drilling the holes and then we fill them at different times of the day so the rock cracks in sequence. We fill the holes at the face of the rock in the morning and work our way backward. The face cracks and falls, then the next level back goes and so on. We then use an excavator once a day for final removal offsite, this reduces the impact noise and vibrations have on the neighbours and allows us to continue working on the dig throughout the day.’ 

‘We use 20kgs of Expando per seven 1.6 metre holes, 38 millimeters in diameter – that’s 2.3 cubic metres of rock removed per 20kg box.’ 

Now you have discovered Expando, would you use it on other projects? ‘Definitely, it’s perfect for confined spaces such as drilling under a house, or whenever vibrations or noise is an issue. It’s also great having a local supplier that you can call upon. The site can only store a small amount of material so John makes regular trips to deliver more Expando’.  

So what will the development eventually look like? ‘We are still planning the finishing touches but eventually this will be a 3000sq metre home which comes complete with a ballroom, 20 seat home theatre, indoor / outdoor swimming pool, a bowling alley, 120,000 litre fish tank, and a badmington court. It will take two years to construct and we are aiming for a 7 star rating BASIX rating’. 

 

As the building and construction industry faces escalating urban density, natural environmental concerns and proximity to cultural heritage areas such as schools and hospitals, controlling construction vibration can be a nightmare.

Complaints from neighbours, council restrictions, crippling project budgets, and damage to adjacent buildings are some of the common impacts from vibration issues.

Now an innovative product called Expando has provided a solution for these difficult sites. Expando – a non-toxic expansive mortar is the ideal solution to crack rocks and concrete without the headache of vibration issues typical of traditional demolition and rock removal methods.

Expando is a non explosive demolition agent with an impressive 14,000 PSI expansive strength that will simplify the process of cutting and breaking rocks or concrete and takes the risk out of difficult excavation, trenching or demolition work.

By using Expando, you can save thousands of dollars and achieve your demolition objectives without having to hire expensive experts or specialised equipment like excavators, jackhammers, concrete saws or use explosive blasting.

Why is vibration an important issue?

Construction vibration levels are set by regulatory authorities such as each state’s Environment Protection Authority (EPA), Standards Australia and local councils*.

The need for such regulation arises as construction equipment (including pile drivers, jackhammers, dump trucks, dozers, excavators and concrete saws) can operate in very close proximity to residential and commercial premises, sometimes for extended daily hours and for some projects, in excess of two to three years. If vibrations are a potential problem, councils may require a dilapidation report on neighbouring properties as part of DA approval.

If vibration levels from construction are too high, then people residing or working nearby may take action or involve councils to restrict construction activities, especially if it can be demonstrated that levels exceed acceptable limits set by relevant standards and regulations. As such, construction vibration can threaten a project's schedule and budget if not adequately addressed.

Vibration – Some of the impacts

Neighbour Complaints due to Human Disturbance

Vibration can potentially impact on an individual’s quality of life or work efficiency. This is especially true for project sites within close proximity to residential or cultural heritage areas such as schools and hospitals.

The vibration criteria for human disturbance tends to be more stringent than for effects on building contents and building structural damage. The table below shows vibration limits for normal construction activities to protect human comfort based on NSW EPA's guidelines. These human comfort limits are intended to minimise annoyance and are below levels required for the prevention of structural damage to buildings (because people can feel vibration at lower levels than what is required to cause damage to buildings and contents)and as such, are considered suitable for use in general assessments.

Table 1 – NSW EPA Vibration Limits to Protect Human Comfort (rms)*
Place	Time	Continuous Vibration	Intermittent Vibration
Residential	Day	0.2mm/s	6.0mm/s
	Night	0.14mm/s	2.0mm/s
Offices	Day	0.4mm/s	12.7mm/s
	Night	0.4mm/s	12.7mm/s
Workshops	Day	0.8mm/s	12.7mm/s
	Night	0.8mm/s	12.7mm/s

Below are some commonly used indicative minimum buffer distances to avoid human discomfort during the day. However, please note that as vibration level depends on many factors and is site specific, these should be used as a general guide only.

Table 2: Suggested Minimum Bugger Distances to Avoid Human Discomfort*
Activity/ Equipment Type	Min. Distance
Rock breaker  (small – large)	5m – 15m
Pulverisor 30 tonne	4m
Bulldozers	5m
Vibratory rollers (light – heavy)	5m – 25m
Truck movements	10m
Sheet piling	50m

Structural damage to buildings

Construction in dense urban settings can result in damage to adjacent structures. Even the most careful planning and implementation can result in damage if adjacent buildings are fragile or especially susceptible to vibration due to demolition and other construction activities.

Currently no Australian Standard exists for assessment of building damage caused by vibrational, however as a guide, the German standard DIN 4150 - Part 3 Structural vibration in buildings – Effects on Structures provides “safe limits” up to which no damage due to vibration effects has been observed for particular classes of buildings.

Table 3: Minimum Safe Limits of Vibration to Reduce Likelihood of Building Damage (rms)*
Building Type	Intermittent Vibration
Commercial & Industrial	20mm/s
Dwellings	5mm/s
Sensitive Structures (eg. historical with preserve orders, etc)	3mm/s

British Standard BS7385: Part 2 Evaluation and measurement of vibration in buildings also sets standards for assessing the likelihood of building damage from vibration.

Reduce construction vibration – Buy Expando today

When construction vibration is an issue for demolition and excavation work in residential settings or sites within close proximity to cultural heritage areas such as schools and hospitals, Expando is the ideal solution for you.
Expando is a non explosive demolition agent that cracks rocks and concrete without the need for blasting or heavy equipment like excavators, jackhammers or concrete saws.

Buy Expando now via our secure online shop, delivered anywhere around Australia. For more information on Expando expansive mortar please contact us.