Portal: General

The COVID-19 Pandemic affected our lives in ways none of us have ever experienced in our lifetimes. I’ve been in construction for 45 years and I have never seen our economy shut down, businesses closed, or people required to stay at home. In 2001, the attacks of September 11th temporarily shut down air travel and the stock market, but the American economy remained intact and air travel resumed within a couple of weeks. However, COVID-19, has affected our lives in ways that we could never have imagined. Schools and universities were closed; professional, collegiate and high school sports seasons were suspended and canceled; and restaurants and businesses were closed. We were told to stay home and work remotely, if possible, and businesses across the country followed those directives.

This is a revised version of the original article printed in the Summer 2016 of Shotcrete magazine before the OSHA rule was put in place. This revision has added site measured values for air monitoring of crew members on shotcrete projects, as well as ASA’s response to OSHA’s request for information in August 2019. Also, included is a short section on applicable respirators. With this revision our intent is to put the current information you need about the OSHA rule and its impact on shotcrete operations in one place for ready reference.

This year, 2020, we have been challenged in a manner unlike anything we have experienced in America since the 1918 influenza pandemic that killed millions worldwide. The coronavirus (COVID-19) was identified in Wuhan, China, after initially being reported as a cluster of pneumonia cases in December 2019. Despite efforts to contain the virus, it rapidly spread to Italy and the rest of Europe and eventually the United States. As a result, on February 26, the first cases of COVID-19 began to appear in the Seattle,
Wash. area. Acting rapidly, many state governors issued
emergency restrictions and stay-at-home orders. Across
America we all watched the coronavirus task force briefings and New York Governor Andrew Cuomo’s morning
broadcasts, as the response unfolded in especially
hard-hit New York. In Pennsylvania we were issued
stay-at-home orders by our Governor Tom Wolf for all
but life-sustaining businesses. Which resulted in PennDOT closing down construction projects. In the months
that followed, state governors began to reopen their
economies. With the return to work there are protocols
and procedures we will need to follow to keep our crews
safe and well. Below are some guidelines and information that I hope you will find helpful.
INTENT OF PROGRAM
COVID-19 is an easily transmitted disease, especially
in group settings. It is essential that positive actions be
implemented to slow or stop the spread of the virus to
safeguard the public safety. Construction is vital to our
nation’s economy. Recognizing this, we need to find
ways to accomplish our work while not endangering
our employees. This requires several precautions to
protect our workers, their families, and members of
the community. It is necessary that all businesses in
the construction industry conducting person-to-person
activities follow the directives and requirements of their
state governments. Other local political units or privately
owned companies may elect to impose more stringent
requirements. In such cases we must adhere to the
client or owner’s requirements.
Recommended Guidelines
• Follow all applicable provisions that your State
government has provided for business safety
measures.
• Requiring that every person present at a work
site wear a face mask or face coverings.
Dealing with COVID-19
in Construction
By Ted W. Sofis
Fig. 1: Social distancing with mask inside Fig. 2: Hand Sanitizer and Disinfectant Wipes
shotcrete.org Spring 2020 | Shotcrete 35
• Establish protocols for action to be taken when
cases or probable cases of COVID-19 are
discovered or whenever people in the company
could have possibly been exposed to someone
who may have the virus.
• Require social distancing with a 6 ft (2 m) minimum distance between workers, unless the safety of the workers makes an exception necessary,
(for example, team lifting.)
• Follow other Department of Health (DOH) and
Centers for Disease Control and Prevention
(CDC) guidance.
• Provide hand washing stations at appropriate
locations on your job sites, such as building entrances, break areas, offices, trailers and job site
egress areas.
• Implement cleaning or sanitizing protocols at all
construction sites and projects. Identify and regularly clean and disinfect areas that are high risk
for transmission. Establish requirements to clean
common areas and regularly trafficked areas
periodically.
• Ensure all gatherings are limited to no more than
the maximum gathering size mandated by the
state where your project is located. Maintain 6 ft
(2 m) social distancing at all times when required
to meet, even when meeting outside.
• Use virtual meetings and distribute information
electronically whenever possible.
• Stagger shifts, work breaks, work areas, and
different trades, wherever feasible, to minimize
the number of workers on site.
• Limit tool sharing and sanitize tools or equipment
if they must be shared.
• Employ jobsite screening based on CDC guidance to determine if employees should be
working. Prohibit employees with any symptoms
of Covid-19 from working. Encourage any sick
employees to stay at home.
• Prohibit unnecessary visitors to any project
or work site and limit the number of supplier
deliveries.
• Limit access to enclosed spaces as much as
possible.
• Ensure workers are traveling to and from the
jobsite in separate vehicles. Whenever possible,
make sure that they do not share a vehicle.
• Identify a Coronavirus Safety Officer for each
project or work site, or (on a large-scale project)
for each contractor or subcontractor at the site.
The primary responsibility of the Safety Officer is
to convey, implement and enforce the social distancing and other requirements of the company
program for the protection of employees, suppliers, and other personnel at the site.
Fig. 3: Social distancing with mask outside
36 Shotcrete | Spring 2020 shotcrete.org
Ultimately, as a contractor, I realize the difficulties
involved in implementing and following coronavirus
guidelines, while at the same time trying to efficiently
perform and complete our projects. The reality is
that we have no other option. This pandemic is so
widespread and highly contagious that it forced
the shutdown of our nation’s economy for months.
Nothing like this has ever happened before in our
lifetimes. To ignore this, we jeopardize the lives of
our employees and their families. For the safety of
everyone involved and the communities where we
live, we need to get through this together. A vaccine
for COVID-19 will be developed and therapeutic
medications for treating the virus will become
available. In the interim, we need to find ways to
be safe and productive. I hope that you find these
guidelines helpful. More importantly, it is my hope that
all of you and all of your employees make it through
this construction season safely and in good health.
Ted Sofis and his brother, William J.
Sofis Jr., are the Principal Owners of
Sofis Company, Inc. After he received
his BA in 1975 from Muskingum College,
New Concord, OH, Ted began working
full time as a shotcrete nozzleman and
operator servicing the steel industry. He
began managing Sofis Company, Inc., in
1984 and has over 40 years of experience in the shotcrete
industry. He is a member of various ASA committees and an
ACI Shotcrete Nozzleman Examiner for shotcrete certification. Over the years, Sofis Company, Inc., has been involved
in bridge, dam, and slope projects using shotcrete and
refractory installations in power plants and steel mills. Sofis
Company, Inc., is a member of the Pittsburgh Section of the
American Society of Highway Engineers (ASHE) and ASA.
Fig. 4: Face mask protection in close proximity Fig. 5: The respiratory protection worn during gunning operations
fulfills the COVID-19 face mask directive.

The decline in the number of workers in the construction industry is a severe problem in Japan. Formwork is indispensable for concrete structures, but due to the shortage of carpenters, formwork assembly tends to be slow and can cause project delays. To deal with this problem, new workers are being hired and formwork carpenters are being trained, but the payoff is not immediate because the acquisition of the required skills takes several years of education and experience. The “formless construction method” that eschews
formwork, might be a possible solution (Fig. 1), substituting an outer shell formed with sprayed mortar. The
reinforced concrete structure is then created by placing
reinforcing bar and casting self-compacting concrete
(SCC) inside the outer shell.
In this approach, the lateral pressure of the fresh concrete stresses the outer shell during concrete casting, so
the shell must have high tensile strength. Since Japan is
an earthquake-prone country, structures are required to
have strong deformation performance and must resist
the large bending and compressive stresses generated during earthquakes. Furthermore, to reduce the life
cycle cost of the structure and increase its sustainability,
both high durability and maintenance-free design of the
structure are required. Thus, the outer shell must have
a high resistance to chloride ion penetration and other
aggressive exposures.
To satisfy the performance requirements, we decided
to use Ultra High Strength Fiber Reinforced Concrete
New Application Method of
Sprayed UHPFRC
By Satoru Kobayashi
Fig. 1: Concept of formless construction method
(UHPFRC) as the sprayed material. UHPFRC is a highstrength and high-ductility material with compressive
strength of 22,000 to 36,000 lb/in2
(150 to 250 MPa)
and tensile strength not lower than 1200 lb/in2
(8 MPa).
It is also characterized by a highly dense concrete matrix
with very low water and air permeability and thus high
chloride resistance. In Japan, UHPFRC has been used
mainly for factory produced precast products. Recently,
with the advent of mass manufacturing of precast members with large sections, the application of UHPFRC
to civil engineering structures has been increasing. The
largest such project to date is the application of UHPFRC for the floor slabs of Runway D at Tokyo International Airport with a UHPFRC volume of approx. 26,000
yd3
(20,000 m3
).
Thus far, UHPFR has rarely been used with sprayed
placement, and forming the outer shell of a structure
with sprayed UHPFRC is a novel challenge. This article
outlines the experimental method developed and used
to form the outer shell of a structure with sprayed
UHPFRC.
We focused on columns as the target structure. This
formless construction method requires a core material
that is easy to install and remove. Air tubes were adopted as the core material. Figure 2 shows the installation
of the air tubes. The thickness of the member was 16 x
16 in. (400 × 400 mm), and the thickness of UHPFRC
was 1.6 in. (40 mm). The height of the columns was 59
in. (1500 mm).
In this experiment, a mortar pump (squeeze type),
maximum discharge rate 8 yd3
/hr (100 L/min) and a
delivery hose with a diameter of 2 in. (55 mm) were used.
Fig. 2: Installation of air tubes
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The diameter of the tip nozzle was
0.6 in. (15 mm). The sprayed material was required to stick on vertical
surfaces without sagging. To this
end, a non-alkali hardening accelerator was added at the nozzle.
Figure 3 shows the spraying of
UHPFRC. The material adhered to
the vertical surfaces of the air tubes
without sagging, and coverage of
the sprayed material to the required
thickness and height of 5 ft (1.5 m)
was achieved without problem.
Figure 4 shows the removal of
the air tubes that was easily accomplished.
As the next steps, reinforcing
bars will be set and SCC will be
cast inside the outer shell. The
structural performance will be evaluated by flexural strength testing.
Fig. 3: Spraying of UHPFRC on air tubes Fig. 4: Removal of the air tubes
Satoru Kobayashi
is a senior
researcher
for Kajima
Technical Research
Institute based
in Japan. He
graduated from
Hiroshima University where he studied
the durability of concrete. He is highly
skilled in concrete, for example, selfcompacting concrete, anti-washout
underwater concrete, dam concrete,
and shotcrete. Recently his research
project focuses on the new application
method of UHPFRC and various
ways to use it at the construction site
effectively in order to improve the
durability of the structure and the
productivity of the construction process.