1

LAYERED SOIL FAILURE The graphic to the right illus-

trates two different trench col-lapse scenarios. The left side depicts a “strong over weak” shear failure in which the top

layer will collapse over the weak-er bottom layer. The second, “weak over strong” shear failure finds the weaker top layer caving

into the trench.

How Trenches Collapse: by Adam Zeciri

Local Technical Assistance Program

N E B R A S K A L T A P

The INTERCHANGE Vol 1: Issue 3: Mar 2013

IN THIS ISSUE

Hyberger-Less Corner

How Trenches Collapse

2013 NE Asphalt Paving Conference

New Online Resources FHWA

E-Learning Updates

Santee’s Mesozoic

Msytery

NE-LTAP’s New CNG Dodge Caravan

Visit our website for additional information and resources at www.ne-ltap.unl.edu

To register for courses go to the following link:

https://services.ne-ltap.org/workshops/

SectionList.aspx

“Digging a trench, throwing in a box and assuming everything is

okay, is essentially rolling the dice with regard to protecting worker

Hyberger-Less Corner

As most of you may be aware, Bob Hyberger has been on a leave of

absence for some time. On March 21st, Bob lost his brave battle with

cancer. Please keep his family in your thoughts and prayers during

this time. If you would like to send a note to his family please contact

us for information. He will be greatly missed by us all.

2 How Trenches Collapse : Cont Pg 1

SLOUGHING [AIR DRYING]

Sloughing occurs when a trench wall becomes so dry that it creates a weak area. Wind blowing into an open trench is a common cause of sloughing. This weak area cannot support the weight of the soil above and will eventually

cause the trench to collapse.

SOFT POCKETS

When an area containing varying soil types is trenched, soft pockets may be encountered. While the trench walls consist of mostly stable soils, soft areas of sandy soil are exposed at depths under the surface. These soft, sandy

areas are weak spots and will cave in, creating a void be-neath more stable soils. Gravity and time will combine to fill the void by way of a trench collapse.

WEDGE FAILURE

One of the ways that the void will be filled is by a wedge

failure. A large section of the trench wall will collapse by

sliding down the shear failure surface and into the

trench. The wedge failure begins as fissures along the

surface of the ground. Gravity then acts to create a frac-

ture that continues from the surface down to the area of

the void, causing the wedge of soil to collapse into the

trench in an angular fashion

SOFT ZONE FAILURE This graphic depicts a trench collapse caused by a soft

zone failure. The soft zone is a layer of soft soil, sand-wiched horizontally between two layers of stable soil. The soft zone causes the top layer of stable soil to have a weak foundation, leading to collapse. The introduction of water

to a stable trench can undermine the soil, creating a soft zone. Soft zones also occur naturally over time as soil lay-ers are formed.

3 How Trenches Collapse: Cont Pg 1-2

ROTATIONAL FAILURE

Another way collapsed soft pockets fill voids is a rotational failure. Here, the wedge failure area doesn’t slide to the bottom of the trench at an angle, but rather rotates downwards in a circular fashion along the shear failure surface and into the bottom of the

trench. Soil failure first occurs at the bottom of the trench which can be seen as budging of the side of the trench.

Essentials: Plasticity and Soil Classification

What does all this have to do with you? It is information vital to work in accordance with OSHA standards. More importantly, it is vital information if you are digging a trench and want to protect yourself and coworkers from a trench collapse. Classifying soil type is a large part of OSHA compli-ance. One of the first questions you should ask regarding the soil at a trench site: “Is this soil plastic

or not?” Perhaps the more common thought process will be, “Is this sandy soil?” or “Is this clay soil?”. No matter how you form the question in your mind, the fact is this: the protection of life and health as it concerns trench safety begins with proper soil classification.

How did the shoring

get installed under

the pipe without plac-

ing a worker in the

unprotected trench?

The ends of this

trench must still be

protected. These may

appear to be small

issues, but many

small issues may add

up to disaster.

4

As long as workers remained between

the plywood shield-ing, they would be working safely. How-ever, if work were

being performed out-side of the installed shielding, they would be working in

an unsafe condition.

If you would like more information on Trench Training con-

tact Don Neary at 402-472-7630.

The type of protective equipment needed to protect workers in a trench is determined in great part

by the type of soil encountered at a job site. Determining the type of soil allows you to take into

account the impact of water in the trench. To remove standing water in the bottom of a trench, dif-

ferent pumps must be used for different soil types. Assessing water content as well as water’s

standing time in a trench is critical in selection of the proper protective equipment needed for a job.

Shoring may not be the right choice; you may need a trench box.

Again, it can’t be stressed enough that trench safety begins with proper soil classification. Whether

soil plasticity exists is a major factor to consider when classifying the type of soil. Soil classification

is crucial to selecting trench safety equipment. According to trench safety experts, workers often

overlook determining whether soil plasticity exists when selecting the type of protective equipment

to employ in a trench. Digging a trench, throwing in a box and assuming everything is okay, is es-

sentially rolling the dice with regard to protecting worker life, health and well-being.

By Adam Zeciri, Editor, Underground Focus. Reprinted with permission - “How Trenches Collapse.” Underground Focus, Volume 26, Issue 5. Manteno, IL 2012. Based on the works of Dr. Felix Yokel

and Dr. Jack Mickle.

How Trenches Collapse: Cont pg 1-3

5

The Annual NE Asphalt Paving Conference celebrated its 57th Anniversary on February 12th in

Kearney this year. The focus of this multi-state, two-day conference is to bring asphalt professionals

together to share research and methodologies to other industry related professionals. Presentations of

improved mixes, application and equipment are all part of this conference as well as presentations on

extending the life of existing asphalt pavements.

This year we had some new vendors come out. Ritchie Bros and Astec Inc, were a couple of them. We

also had Cabela’s come out to provide entertainment for our social hour. They provided hunting games

for the Wii and XBOX.

We also had a lot of great topics that was discussed such as Hot Mix Applications and Cost, Fraction-

ing RAP, and Emulsions 101 Virtual Lab Tour. Something new we tried this year was we had three

breakout sessions: Design, Construction and Maintenance, each breakout had topics of discussion

based upon the breakout title.

Thanks to all those who came out and we hope to see you again next year. If you haven’t attended we

would love to have you come out! Below are some pictures taken from the Asphalt Conference, Enjoy!

Attendees having a good time during a

break.

Dan Cady and Bill Bivin from NE-LTAP

getting ready for the day!

2013 NE Asphalt Paving Conference: by Torina Haase

6 NE Asphlat Conference Cont. from Page 5

Robert Rea from NDOR giving his

Welcome speech!

Dan Cady invited the Color Guard from the University of Nebraska– Kearney US Army ROTC out

to post the colors, what an awesome job they did. Thanks!

“You want to take a picture of me???”

7 Ne Asphalt Conference, Cont. from Page 6

Exhibitors/ Vendors

Nebraska Environmental Products NMC/CAT

Light & Siren

8

New Online Resource Helps Local Government Deliver Federal-Aid Projects, by: FHWA

Local public agencies (LPAs)—mostly counties, cities and towns—own and operate the vast majority of

the nation’s highway system. The nation’s local roads network comprises about 3 million miles, or nearly 75 percent, of the overall system, and more than half of the bridges. Local public agencies build and maintain the local roads network using a variety of funding sources, including the Federal-aid Highway Program. Every year LPAs administer about $7 billion in Federal-aid projects, which can range from

short sidewalks and bike-pedestrian facilities to pavement overlays and bridges. When LPAs receive Federal-aid funding, they begin a process of working closely with their respective state department of transportation (state DOT) to meet all Federal-aid requirements, such as environ-mental reviews, civil rights compliance, right-of-way acquisitions, safety, and construction and contract

administration. Understanding Federal-aid requirements is critical to the successful delivery of federally funded projects at the local level. Non-compliance can lead to project delays and LPAs not receiving time-ly Federal-aid reimbursements. To help LPAs meet their Federal-aid requirements, the Federal Highway Administration (FHWA) recently

launch a new information-sharing initiative, called Federal-aid Essentials for Local Public Agencies, that offers an abundance of information about key aspects of the Federal-aid program on a single public web-site. The Federal-aid Essentials website features a resource library of more than 80 informational videos and

related materials. The videos focus on a single topic in the most critical areas of Federal-aid. The videos are relatively short at less than 10 minutes long, professionally narrated in non-technical language, and supported with engaging graphics and animation that give viewers the most essential content. The vide-os can be viewed in any sequence from any computer or mobile device with Internet access.

When users first enter the Federal-aid Essentials website at www.fhwa.dot.gov/federal-aidessentials, they will be greeted with a brief introductory video about the Federal-aid Essentials initiative and how to navigate the Web site. From there, users will have access to the resource library via a convenient drop-

down menu that presents seven categories of video modules:

Federal-aid Program Overview Civil Rights Environment Finance

Right of Way Product Development Project Construction and Contract Administration

After choosing a category, a menu of video modules for the specific category appears next to the video

viewing screen. Users simply click on the desired video title and the presentation begins. On the same page, users have access to a wealth of companion materials, including a written, printable script of each video, the applicable Code of Federal Regulations, helpful reference information, and links to additional online resources. Another function allows users to give feedback on a particular video, the full resource

library and the website itself.

9

New Online Resource Helps Local Government Deliver Federal-Aid Projects, Cont. Pg 8

If users have questions about a particular video’s content or about the Federal-aid program in general,

they can click on a State Resources button on the main page and gain access to a list of useful infor-mation, including individual state and FHWA local office LPA coordinator contacts and web links to state DOTs, state LPA manuals, local technical assistance program (LTAP) centers, and other helpful online resources. A drop-down menu on the main page, titled “I want to know about…,” helps users find infor-

mation quickly and conveniently about common Federal-aid topics. The site is regularly updated and new features added to meet state DOT and LPA needs and requests. Since the modules are available anywhere there is Internet access, they can be used in a multitude of settings on any Internet-ready device. They can be shown at meetings, viewed in one’s office or viewed on

a job site using a laptop computer or mobile device. A project team can access the videos on a minute’s notice anytime, anywhere for discussion with stakeholders and partners. After viewing the videos, view-ers acquire enough knowledge to know what questions to ask their state DOT counterparts, what appro-priate technical terminology to use, and how and where to get additional assistance. State DOTs and

LPAs also can use the videos to augment training at the local level.

The Federal-aid Essentials website helps LPAs understand their Federal-aid requirements as they pur-sue better, faster and smarter ways of delivering the Federal-aid program at the local level. You can read more about the Federal-aid Essentials initiative in FHWA’s Public Roads magazine at

http://www.fhwa.dot.gov/publications/publicroads/12septoct/03.cfm. For more information on this initiative, please e-mail the Federal-aid Essentials for Local Public Agencies

program at LPA-feedback@dot.gov.

10

E-Learning Update: by, Bill Bivin

We have a full day course in Pavement Design offered by the Nebraska Department of Roads Material & Re-

search Division for engineers that are involved in designing pavements in Nebraska for state and federal aid pro-

jects at all levels. This training is optional but will provide the documentation to show experience in pavement

design which is required by NDOR. Project deliverables are: Typical Sheets for Project Plan Packages, Pave-

ment Determination Data Sheets, Pavement Design Analysis (AASHTO Method will be covered), Strategy Types

and Selection, For Public and Private Pavement Design Engineers who work on Federal Aid Projects.

NDOR’s Local Public Agency Right of Way Training Course is a self-directed course for Local Public Agencies

who will learn step by step procedures and practices for the fair and comprehensive acquisition of property need-

ed for the completion of publicly funded local projects. The course covers Understanding of the Uniform Act,

Understanding the Laws that Govern, Understanding ROW process for LPA, and Understanding the Compensa-

tion Estimate.

In addition the Nebraska LTAP offerings, campus.extension.org, has a wide variety of courses in subjects such as

Community Development, Energy, Environment, Economics, Home and Family, Agriculture and Animals, Pest

Management, and Gardening.

11

Santee’s Mesozoic Mystery: By Alan J. Bartels, Illustrations by Mark Marcussen

ON NEBRASKA’S NORTHERN border, the Missouri River rhythmically drains the Great Plains as it has

for uncountable eons.

But even this ancient prairie river is a relative newcomer on the geologic landscape compared to the

treasures sequestered in the high hills ringing this broad river valley.

Long before the ceremonial drums of the Santee Sioux echoed from this land, this area was the floor of

an ancient inland sea that stretched from the Gulf of Mexico to Canada. Strange creatures such as am-

monites, giant clams, plesiosaurs and huge filter-feeding fish inhabited the depths. Sharks that made

their brethren of today look like minnows hunted here. But even those toothy prehistoric predators were

on the seafood menu for other aquatic giants.

Fast forward 75 million years to a road in modern-day Knox County on land owned by the Santee Na-

tion.

Passing through the community of Santee, we drive along the south bank of the Missouri and then turn

south at the 1884 Gothic-style Church of Our Most Merciful Savior. The unmerciful drought coupled

with a road-construction project conspire to form the miles-long dusty plume we trail in our wake. We

pull over at the crest of the Missouri’s valley and when the dust cloud settles, we can still see north to

her flowing ribbon of blue.

To the south, bright yellow backhoes and bulldozers billow black clouds as a trio of men wearing grins

as wide as children on Christmas morning brush away dust and dirt from what is as precious a gift

from the ground. This paleontologist’s present was wrapped for millions of years, protectively packed in

the surrounding soil, until a road grader’s hardened steel blade opened it while sculpting the ditch.

Knowing that whenever highway construction disrupts the earth’s surface there is a possibility fossils

will be uncovered, Nebraska State Highway paleontologist Shane Tucker was on site when machines

peeled back the layers of time.

Fossil hunters like Mike

Voorhies, left, dig into the past to reveal glimpses of

this lost world.

Creatures we would consider

to be monsters today were com-mon in the in-land sea that

once covered much of what is now North America.

12

Santee’s Mesozoic Mystery Continued

When a shiny black tooth was revealed to the sunlight for the first time

in millions of years, the machinery jogged down the road a bit to work

while Tucker dug deeper, hopeful that other remains, well, remained.

Soon, time’s treasure chest opened just far enough to reveal a tantaliz-

ing trove of more than just teeth.

Realizing the immense value of Nebraska’s ancient treasures, in 1959,

the Unicameral bolstered protections enacted by the Antiquities Act of

1906 and allowed the Nebraska Department of Roads to work with the

Nebraska State Historical Society and the University of Nebraska State

Museum for the protection of paleontological remains and archaeologi-

cal artifacts found during road projects. Nebraska was the first state in

the nation to create such a program.

Near the Church of Our Most Merciful Savior, Missouri River cliffs show layers from a time long before the es-tablishment of this reservation.

13

Santee’s Mesozoic Mystery Cont.

Tucker’s troops include fossil hunter Mike Voorhies, who discovered the now world-renowned Ashfall

Fossil Beds site near Royal, and the minder of millions of bones, George Corner, manager of the Univer-

sity of Nebraska State Museum’s collections.

As the Nebraska wind swirls the reservation’s dirt as if trying to reclaim the find, the trio carefully

pick the matrix from around teeth and bone, brushing away the past from the skull of a savage marine

predator, the mosasaur.

With dozens of 3-inch-long, flesh-chopping teeth arming its 3-feet-long skull, the lizardlike mosasaur

reigned as the top link in the inland sea’s prehistoric food chain.

With some found that were 30 feet long on the fin, the mosasaur was a true giant of a beast. But

stumbling upon a creature even as large as this can be like finding a fossilized pine needle in a Mesozoic

haystack.

“It’s difficult for crews up in those machines to see this kind of stuff,” Voorhies said. “You hear some

legends that once road crews find bones, entire projects are stopped. That’s not true. Once they’ve seen

it, it’s easy to swing around a little thing like this. They have their job and Shane has his.”

With no delay in construction, and in only three days, the bone collectors have isolated the skull and

applied a protective plaster cast. Before being exhumed from its ancient grave, a Santee delegation led

by a tribal elder arrive to meet the paleontologists and stake claim to the ancient treasure. Then, the

treasured youth of the next generation, 110 in all from Santee Community School, arrive to take ad-

vantage of the unique educational opportunity.

“The Highway Paleontology Program has collected more than 200,000 specimens, including several spe-

cies that are new to science,” said Tucker while handing fossil ammonites and shark’s teeth among the

students.

“Each fossil is a piece of a puzzle and the more pieces we have to study, the better, clearer picture we

have of Nebraska’s prehistoric past. Each day leads to new discoveries that stimulate curiosity and in-

spire students of all ages to learn more about our state’s rich natural heritage.”

After taking in the ancient treasure of the Santee, and asking Tucker a hundred questions he’s an-

swered thousands of times, the children reluctantly gather in the buses.

“How many students can say one of their most cherished memories was going to a fossil site and watch-

ing a huge, multimillion year-old fossil being dug out of the ground?” said Santee High School social

studies teacher, Sheri Plumbtree.

Dust devils erased the children’s footprints as the buses pulled away, and we strained to hear the pulse

of ancient drums along the Missouri. We truly live in a unique and mysterious part of the world.

If you are interested in subscribing to receive more interesting articles please visit:

www.nebraskalife.com/?page_id=45

Reprinted with permission from Alan Bartels, Field Assistant Editor, Nebraska Life Magazine. Thank

you.

14

Santee’s Mesozoic Mystery Continued

Fossil hunter Mike Voorhies and Ne-braska highway salvage paleontologist Shane Tucker work with George Cor-ner, collections manager for the Uni-versity of Nebraska State Museum, to excavate the Santee mosasaur after construction equipment exposed it during a road-improvement project near Santee. The beast inside the stone was a top predator of the Meso-zoic and was armed with a jawful of massive flesh-tearing teeth.

15

NE-LTAP’s New CNG Converted Dodge Caravan

We love the cool design. We bleed RED.

This is where we fill the van with CNG, it took $13.42 to fill

her up…… I remember those days when regular gas was that

A big Thank

You to Black

Hills Energy!!

16

NE-LTAP’s New CNG Converted Dodge Caravan

The above picture is

the CNG 11 gallon

tank located in the

back of our van. The

one to the right is the

cover we use to cover

the CNG tank allow-

ing us to travel with

our necessities for

classes.