Kamppi Center 2002-
This article is published in Instantel's newsletter "Just for the record" (Vol. 3, 2/2003).
When you’re blasting only a stone’s throw from thousands of computers and directly over a downtown subway station, your charges better be precise. An innovative Internet link to monitors eliminates doubt – and quickly!
As a large city block in the heart of Helsinki is blasted apart by explosives, nearby shoppers, commuters and office workers hardly notice. And that’s the plan. Formerly a bus parking lot, this prime real estate in Finland’s capital is being remade into the Kamppi Center, a multipurpose commercial, residential, retail and transportation district.
Begun last September, it’s the largest single construction project to date in this nation. SRV Viitoset Oy is the lead project management contractor.
More than 1,500 individual blasts are anticipated in the removal of over 200,000 cubic meters of rock from the site. But every blast has to be precise. Nearby are hotels and office buildings with thousands of computers. Below ground is a downtown subway station. And the contractor faces hefty fines of US$8,000 to $40,000 per blast for blast violations.
Close monitoring of each blast is therefore crucial. Yet an innovative monitoring system with a link to the Internet lets observers worldwide follow the dynamics of every blast virtually as they occur.
MONITOR ANYWHERE
Kalliotekniikka Oy, the vibration consulting company based in Helsinki, developed the Kamppi project vibration control system and Internet link called BlastView.
“The system was based on a scaled distance that would allow use of information from all previous blasts to help design the next blast sequence,” says Pertti Paavola, MSc, and managing director at Kalliotekniikka Oy. Throughout his 15-year career with the firm, Paavola has been involved with approximately 4,000 different projects.
A total of 35 Instantel Minimate Plus remote vibration monitoring instruments were placed in nearby metro locations and facilities. Linked to Instantel’s Blastware software, the monitors record and send blast data from all measuring points to the Internet for viewing on remote computers within three minutes of a blast.
Also, the mapping software application developed by Kalliotekniikka helps gather three-dimensional distances of individual vibration sensors from the blasting areas.
Paavola explains that results of each blast are reviewed using the Blastware’s scaled distance function, including charge per single hole, charge per delay, and the total charge weight.
“Within a few minutes after each blast, the blasting contractor is able to obtain the information and determine whether to continue blasting as planned, or to modify the blast design to improve performance,” Paavola says.
THE KAMPPI CENTER
When fully operational by autumn 2006, the Kamppi Center will feature a new underground long-distance coach station, retail outlets and commercial offices. Apartment buildings and a five or six-story department store will also be built, accessible from underground parking facilities.
Yet in this project, “Protecting the surrounding buildings and facilities from the effects of blasting is a very difficult task,” says Paavola. In close proximity are:
The Kamppi metro station, only 8 m below the lowest blasting level. Vibration limits of 10 mm/s are allowed during the day, when the metroline transit system is in operation, and 30 mm/s at night.
Facilities under or beside the blasting area, including a sewage tunnel, multipurpose tunnel, large car parking area, and a Helsinki Energy transformation station within 50 m of the blasting area.
Two hotels within several meters, and two museums within 100 m.
Approximately 10,000 computers in office buildings within 100 m.
LOG ON WEB SITE
Attendees of the ISEE (International Society of Explosives Engineers) annual conference in February saw the monitoring system in action.
“We logged onto the Kalliotekniikka web site and through a video cam mounted on a tower crane, watched several blasts occur,” says Ron Mask, Instantel’s Sales Manager. “We actually saw the blasting mats heave up in a puff of dust. Then within two minutes we were able to visit another part of that web site and view the actual vibration values and graphs to ensure they met the strict vibration limits.
“It’s the most impressive information-gathering, collecting and distribution method in the blasting world,” he says. “Historically, blast data has been collected manually from the sites, and it’s very labor intensive. Now we’re automating data collection by sending it wirelessly to a central location for processing, and then to the right hands as quickly and efficiently as possible.”
Data processing speed is indeed important for blasting that is confined to narrow time windows.
“If necessary, blasting contractors can quickly analyze and change the charge weights and sizes of explosives, and get more blasts done within the time limits,” Mask explains.
“To me, it’s all about optimization and doing the blasting on a very tight schedule,” says Mask. “This system is ideal for projects like the Kamppi Center - where blasting is very restricted in time and there are lots of instrumentation and monitoring points.”
For more about the Kamppi Center project and its construction, visit www.kampinkeskus.fi and www.instantel.com.
Reprinted with permission from the Summer 2003 issue of Worldwide Projects, the quarterly international magazine for major construction and mining projects. For free subscriptions, visit www.worldwideprojects.com, or contact info@worldwideprojects.com.
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