Memo Design Issues Relating To Mainstreet•
CITY OF HOPKINS
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DATE: July 11, 1991
TO: Mayor and City Council
FROM: Lee Gustafson, Public Works Director
SUBJECT: Design issues relating to Mainstreet
At the June 25th and July 2nd City Council meetings,
information was given to the City Council regarding
Mainstreet design issues. The information contained brief
summaries of certain design issues that needed clarification
prior to commencement of the Mainstreet project. The design
issues in question were tree location, brick paver design,
8th Avenue nodes, and the 9th Avenue Plaza.
Is The attached memorandum from Dick . Koppy, attachment A,
addresses each one of these issues in greater detail with
the exception of the 9th Avenue plaza which will be
addressed in a separate memorandum from Tom Harmening. Mr.
Koppy's memorandum also addresses one issue not previously
discussed with the City Council and that is the Mainstreet
signing plan. Staff recently requested Mr. Koppy to prepare
such a plan in order to insure that the signing blends in
with the aesthetics of Mainstreet, and also that it reflects
the concerns of the property owners and Public Works
department staff.
TREE LOCATIONS: When RLK staff met with the Mainstreet
property owners earlier this year several people expressed
concerns regarding the locations of the new trees. Staff
therefore decided that it may be a good idea to once again
review this design feature due to the number of comments
received.
In the attached memorandum two alternatives are discussed
with respect to tree location. The first alternative is to
leave the trees in the exact location shown on the plans.
The second alternative would allow RLK the flexibility to
move the trees up to 10 feet in either direction from the
location indicated on the plans. Staff concurs with Mr.
Koppy's recommendation to implement option two 'inasmuch as
it will give the property owners some flexibility in the
tree location while maintaining the aesthetic concept
intended for Mainstreet.
July 11, 1991
Page 2
L
•
BRICK PAVERS: Over the -past few months concerns have been
raised regarding the use of brick pavers along the,sidewalks
of Mainstreet. These comments were mainly with respect to
material and installation techniques, safety of brick pavers
and the patterns of the brick pavers. Staff once again felt
that this was an item that should be reviewed prior to
construction.
Mr. Koppy addresses each one of these concerns in his
memorandum and also briefly describes how the present "door
marker" design was chosen. He furthermore addresses options
that are presently available with respect to changing the
design pattern for the brick paver. After reviewing this
information staff concurs with Mr.'Koppy's recommendation
that the proposed door marker design be continued unless
there is an unusual design condition that would suggest
otherwise.
8TH AVENUE INTERSECTION LAYOUTS: The concept of placing
nodes on 8th Avenue similar to the intersection was a strong
concern expressed by Dale Lommen, property owner of the
Little Blind Spot, during RLV s property owner meetings.
Staff felt that the concern submitted by Mr. Lommen
justified reviewing this, design item and consequently
requested RLK to determine if nodes could in ,fact be
installed at the 8th Avenue intersection.
The review performed by RLK for this intersection included
operation of traffic signals, turning movements, bus
operation, and overall traffic,that would be generated from
the proposed theater development and the Ryan retail center
project. The results of this review indicate that it is
possible to install nodes on 8th Avenue without
significantly impacting traffic movement. Furthermore, if
at some future date traffic volumes, warrant the removal, of
the nodes, the nodes can be removed without impacting
adjacent features. Staff therefore concurs with Mr. Koppy's
- recommendation that nodes be placed on 8th Avenue similar to
the other Mainstreet intersections.
SIGNING PLANS FOR MAINSTREET:
signing plan is being prepare(
blend in aesthetically with the
that they reflect the concerns
Public Works staff. A draft of
to Council at the meeting.: The
informational purposes only, no
As mentioned earlier, the
I to insure that the signs
other improvements and also
of the property owners and
this plan will be handed-out
plan is being presented for
other action is required.
•
July 11"1991
Page 3
RECOMMENDED COUNCIL ACTION
1. Motion authorizing the Mainstreet project manager the
flexibility in moving the new trees 10 feet from either
side of their proposed locations as outlined in the
report contained herein.
2. Motion directing staff to proceed with the present
brick - paver concept incorporating door markers as
outlined in the report contained herein.
3. Motion directing staff to install nodes at the 8th
Avenue intersection as indicated in Attachment A,
Figure No. 9, alternative 2 of this report.
4. Motion directing staff to continue with the Mainstreet
signing plan.
UPDATE BY PROJECT MANAGER
Dick Koppy will be handing out copies of work activity
reports, incidental reports and a project budget station at
the end of the Mainstreet discussion. Mr. Koppy would like
to spend a few minutes discussion these items so Council is
award of the procedures he is using on the project.
922 Mainstreet
Hopkins, Mn.
JR 55343
(612) 933 -0972
SSOCIATES LTD. fax: (612) 933 -1153
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MEMORANDUM I/W?C`IIVAI
DATE: JULY 9, 1991
TO: LEE GUSTAFSON, DIRECTOR OF PUBLIC WORKS
FROM: DICK KOPPY, CONSTRUCTION MANAGER
SUBJECT: COMMUNICATION ITEMS -- MAINSTREET PROJECT
INTRODUCTION: At the July 2, 1991 City Council meeting, information
on several items relating to the Mainstreet Construction project was
transmitted to the City Council members. The items, listed below,
relate to design and construction issues that are scheduled for the
City Council review on July 16th. Within this memorandum each of
these items is clarified, feasible alternatives based upon design
considerations and economics are explored, and recommendations are
noted.
o Tree spacing /location with respect to storefront visibility
o Brick paver design and safety aspects
0 8th Avenue intersection design, node placement
o Informational and regulatory sign plate design
0 9th,Avenue Plaza, Clock Tower and Kiosk design and
construction details
TREE LOCATIONS: During the property owner meetings of May and June,
1991, several property owners expressed concerns about the design
locations of the new street trees. Their interest focused upon the
blockage of the business signs and /or the loss of visibility of their
store fronts. Concerns were primarily related to Segment No. 3
between 5th and 11th Avenue where the business density and the tree
spacing is higher. Segment No. 3 includes 8 trees per block compared
with 5 to 6 trees per block in Segment No. 4, west of 11th Avenue to
Shady Oak Road. Figure No. 1 shows the tree spacing between 8th and
9th Avenue.
Two alternatives are suggested for further consideration. The first
option is to leave the trees in the exact location as shown on the
plans. This will maintain the design spacing that is approximately
60 feet. With the street light poles uniformly positioned in the
area between the trees (see Figure No. 1), maintaining the tree
spacing will preserve the anticipated esthetics. A second option
that is suggested allows the movement of the trees up to 10 feet in
either direction dependent upon the individual circumstances of the
store front, sign location and other unique conditions such as
awnings and store entrances. Under this option, design flexibility
is allowed where necessary, yet the design intent is maintained.
It is recommended that the second option be implemented with limited
discretion granted the property owner and the construction manager.
• Civil Engineering • Transportation • Infrastructure Redevelopment
• Landscape Architecture • Construction Management
Memorandum to Lee Gustafson, July 16th City Council items Page 2
The property owners that have expressed tree location concerns will
be notified of the City Councils action, and the appropriate action
will be taken on each Mainstreet property.
BRICK PAVERS: Concerns have been expressed about the use of brick
pavers in the sidewalk area of Mainstreet. The pavers are primarily
located in the corner node areas between 5th Avenue and 20th Avenue.
Figure No. 2 demonstrates the use of the pavers in one of the corner
node areas. Additionally, they are proposed to be used in the 9th
Street plaza and between 5th Avenue and 11th Avenue in front of
building doorways as "door markers ". Figure No. 3 illustrates this
design feature.
During the winter of 1990 and 1991, the Design Review Committee (DRC)
reviewed the use of brick pavers. Several alternatives were examined
with respect to the type of brick pavers and the installation
techniques. Some members of the DRC were concerned about snow and
ice removal and the safety aspects. However, it was pointed out that
concrete sidewalks would have nearly the same safety concerns.
Design patterns on Mainstreet were reviewed closely by the DRC
membership. Some of the options are shown on Figure Nos. 4 & 5.
After considerable discussion, the brick paver use was decided to be
included in the project design in a manner shown on Figure Nos. 3 and
6.
There are three issues that are related to the use of brick pavers on
Mainstreet. They are listed below and discussed thereafter:
1. Type of brick pavers and installation techniques
2. Safety of the brick pavers in front of building doorways
3. Patterns of the brick pavers to be used on Mainstreet
There was a concern that the brick pavers did not have mortar joints
such as the brick pavers that were installed in downtown Rochester.
The brick pavers that are planned for Hopkins have a ' sandset joint
and are similar in design to the brick pavers in front of City Hall
near the flag pole plaza. The pavers with a sandset joint, on a
compacted granular base when bordered by a concrete edge, is a cost -
effective and low maintenance paving system. The pavers proposed on
Mainstreet should be as maintenance free as a poured concrete
sidewalk. The Rochester installation has been reviewed and according
to the City Design Engineer the brick and mortar design does involve
an on -going maintenance program. The rigid joints, setting bed and
concrete base have variable expansion ratios in the freeze /thaw cycle
and depending on location, repair of damaged sections occurs on a
yearly basis. The City of Rochester is still experimenting with
mortar and setting bed alternatives to alleviate this problem.
Tim Erkkila of Westwood wrote a memorandum in May, 1991, on the
safety aspects of the brick pavers in a winter seasonal condition.
Memorandum to Lee Gustafson, July 16th City Council items Page
His memorandum is attached to this report as Attachment ". Based
upon Mr. Erkkila's conclusions, it is suggested that the brick pavers
specified in the Mainstreet project are as adequate as any other
construction material that could be used in a sidewalk location.
It is important to mention that it would be difficult to change the
materials at this time because the contracts were bid and awarded
based upon the brick pavers specified in the Mainstreet plans and
specifications.
If desired, the design pattern demonstrated in Figure No. 3 could be
changed. Alternatives to the Door Markers include using a lineal
pattern perpendicular to the curbs and building face, or a lineal
pattern parallel to the curbs connecting the nodes and the tree
planters. These are shown on Figure No. 5. If either of the
alternatives are accepted, there will be an additional cost. The
table below indicates the three alternatives and the cost estimated
per block for each.
Door Markers, as planned $2,200 per block
Brick bands perpendicular to curbs $5,000 per block
Brick strip from corner to corner $7,000 per block
It is recommended that the proposed door marker design be confirmed
and that no changes on this item be made at this time. If the brick
banding or the brick strip alternate were chosen, additional costs of
$50,000 to 75,000 for the entire project would be necessary because
of the increase in the volume of brick that would be used. Individual
design of the door markers will be done with the consultation of the
property owners. However, it is recommended that the door markers be
used at all doorway locations to the Mainstreet buildings, unless
there is an unusual design condition that would suggest otherwise.
8TH AVENUE INTERSECTION LAYOUT: Most of the intersections of
Mainstreet between 5th Avenue and Shady Oak Road are planned to have
nodes constructed. Only in those intersections with a high traffic
condition such as 5th, 8th, 11th, and 17th Avenue, or where bus stops
affect node layout, 7th Avenue, will the nodes be left out. Where
they are constructed, the nodes will be on the opposite sides of the
intersection of the approach traffic. Two lanes will be available
for the approaching vehicles. However, only one lane will be
available as vehicles leave the intersection. A typical intersection
node layout is shown on Figure No. 7.
Dale Lommen, property owner of the Little Blind Spot located on the
north side of Mainstreet between 8th and 9th Avenue, has expressed a
concern that all of the intersections of Mainstreet have nodes
included. He is concerned that without the nodes, excessive speeds
and drag racing of vehicles will ensue. His primary interest was for
Memorandum to Lee Gustafson, July 16th City Council items Page 4
the intersection of 8th Avenue. However, he requested that the
intersections of 11th Avenue and 17th Avenue be examined.
The DRC examined the design of the nodes during their numerous
sessions last winter and concluded the current design was the most
fair for vehicle operation, pedestrians, and the esthetics of the
streetscape. The members agreed that without the nodes, speeds of
the vehicles could become a serious problem.
Nodes were not recommended at 5th, 8th, 11th, and 17th Avenue because
of traffic movement concerns. Level of Service (LOS) on Mainstreet
was reviewed based upon operation of the traffic signals, turning
movements, bus operations and overall traffic volumes of Mainstreet
and the cross streets. Figure No. 8 includes a sketch of the overall
Mainstreet layout with the major intersections and collector routes
shown. Generally, the LOS is at a 'B' or 'C' level at all the
intersections.
If nodes are added at 5th, 8th, 11th and 17th Avenues, the LOS would
be affected. Current and projected traffic at 11th and 17th Avenues
minimize the attraction of the nodes at these locations. 5th Avenue
is in the same category but it is also outside the project area.
With nodes effecting the high turning movement activity, the LOS
would be lowered to the 'D' level at 5th, 11th and 17th Avenues.
A review of existing traffic at 8th Avenue would place it in a
category where nodes could be placed. Adding in projected traffic
from the proposed theater development project and the Ryan retail
center project increases traffic to a condition where the node
placement is borderline, i.e. the LOS is between 'C' and 'D'. It is
difficult to predict exactly how traffic will operate on Mainstreet
with these two developments. A share of the new traffic from both of
the developments is already calculated as using Mainstreet because of
the redevelopment nature of the new enterprises. However, there is
little doubt traffic will increase on Mainstreet and 8th Avenue from
the developments.
There are two alternatives for the 8th Avenue intersection that are
shown on Figure No. 9: (1) Use no nodes as per the existing design;
or (2) Place nodes on opposite diagonal corners as per the design of
the other intersections where nodes are to be placed. The nodes
could be removed in the future if traffic becomes a serious
congestion problem. It is recommended the nodes be placed as shown
on Figure No. 9, alternative 2.
INFORMATION AND REGULATORY PLAN FOR SIGNING OF MAINSTREET:
The Mainstreet signing plan will incorporate all of the proposed
regulatory, informational and directional signage necessary and
proposed for Mainstreet between 5th Avenue and Shady Oak Road. The
Memorandum to Lee Gustafson, July 16th City Council items Page 5
objective of the sign plan is to provide an informational, creative
and easily recognizable signage system for the City of Hopkins.
Specifically, issues to be achieved will be:
- Reduce the clutter and number of sign locations
- Creative /exciting design theme
- Design theme tailored to Hopkins
- Cost effective in materials /maintenance
- Conform to necessary codes and regulations
The sign plan base map will be drawn at 40 scale with the proposed
curb line, trees, light locations and building facades identified.
Alternative design schemes for the individual signs will be presented
to staff for comment and input. The final product of the
Comprehensive Sign Plan will identify a Hopkins standard for color,
size, pole, and location for all signage on Mainstreet.
A draft of this plan will be discussed at the Council work session
prior to the City Council meeting.
PLAZA DESIGN DETAILS INCLUDING THE CLOCK TOWER AND KIOSK: The reader
is referred to the Memorandum dated July 2, 1991 from Tom Harmening
to the City Council on the Clock Tower -- Plaza subject. The concern
of the construction manager is the coordination of the clock
tower /kiosk work activities with the construction of the plaza
scheduled for September and October, 1991. Mr. Harmening has
detailed the coordination process in his memorandum.
Figure #1: Tree and street light pole locations between 8th and
9th Avenue
Figure #2: Brick pavers used in a corner node area.
Figure #3: Brick pavers used in door marker locations on a
typical block (plan view)
Figure #4: Alternative paver design (plan view)
Figure #5: Alternative paver design; Entire block
Figure #6: 3D view of the brick pavers along Mainstreet.
Figure #7: Typical intersection design showing the node
placement.
Memorandum to Lee Gustafson, July 16th City Council items
Figure #8: Mainstreet Layout
•
Figure #9: 8th Avenue node design, with and without nodes.
Page 6
Attachment: Erkkila's memorandum on the safety aspects of the
" " brick pavers during the winter season.
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PAGE 1 OF 2
X X X O R A N D U M
To: Dick Koppy
From: Tim Erkkila /Randy Goertzen
Date: May 13, 1991
Re: Comparison of "Pavers" to Standard Concrete Sidewalks
14180 Trunk Hwy. 5
Eden Prairie, MN 55344
612- 937 -5150
FAX 612.937 -5822
This is in regard to your inquiry for information on the basic safety of using
precast concrete pavers in the downtown sidewalk. Generally, there are a lot
of misconceptions about this which were caused by the previous misuse of
"bricks" or "tile" (which we aren't using, vs. precast concrete pavers, which
we are using). Westwood has researched this topic and provides the following
information.
The National Concrete Masonry Association has endorsed an article entitled
Design and Construction of Interlocking Concrete Block Pavements by B. Shackel
which states, "Block pavements have been shown to maintain satisfactory levels
of skid resistance in service. The skid resistance tends to be equal to that
associated with grooved rigid pavements and usually equals or exceeds that
associated with asphaltic surfaces." Westwood has interpreted "grooved rigid
pavements" to mean an outdoor concrete surface with control and construction
joints and "asphaltic surfaces" to mean an outdoor bituminous surface.
Also included in the National Concrete Masonry Association's (NCMA) technical
specification data (May 1989) for interlocking concrete pavers is a reference
to snow removal characteristics of pavers. The NCMA states, "Snow is removed
as with any other pavement. The high strength and density of pavers enables
them to resist deicing salts better than conventional asphalt or concrete
paving."
Westwood understands that north- facing buildings in a downtown will typically
experience more problems with snow removal and ice buildup than south - facing
buildings. However, given the aforementioned data from the NCMA, Westwood
does not anticipate that interlocking concrete pavers will contribute to this
problem and that they in fact may help alleviate a portion of this concern by
the property owners.
If the product was inherently inferior for its intended use, we would expect
it would be removed from the market. As this has not occurred, we are not
aware of any serious problem with this material. In summary, our experience
seems to be supported by the industry; precast concrete pavers, properly
installed and maintained, should perform as well as a standard concrete
sidewalk
Attachment
cc: Tom Harmening
Lee Gustafson
Wesiwoee irel -al Semces. Inc s an mal ""nun" emelimr
MAY 09
s: N C M A ATTACHMENT #5 75; P02 PAGE 2 OF 2
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Surface characteristics
In the case of the surface characteristics of blocc pavements the following
conclusions may be drawn:
a) Block pavements exhibit much higher luminance factors under both daylight
and artificial light than bituminous surtacea.
b) Based on objective measurements block pavements give lower standards of
riding quality than asphalt pavements. The riding quality, however, tends to
improve under traffic. At speeds below about 70 km /h surveys of road users
indicate that blocs pavements are perceived to provide a ride quality equal to
that of alternative types of road surface.
C) Block pavements have been shown to maintain satisfactory Levels of skid
resistance In service. The skid resistance tends to be equal to that associated
with grooved rigid pavements and usually equals or exceeds that associated with
asphaltic surfaces.
d) The traffic noise associated with block pavements !s similar to or less than
that associated with asphalt pavements where the surfaces are dry. However, in
wet conditions, block pavements have been reported to be quieter overall than
asphalt surfaces.
e3 In the long term block pavements become effectively impermeable. However,
some water infiltration may occur, especially in the early life of the pavement.
•
Stn+etural Characteristics
Under traffic, block pavements exhibit the following characteristics:
a) The block layer is not merely a decorative wearing surface but often
represents the principalloadbearing course.
b) For a given thickness of pavernernt and a given traffic volume block
pavements usually exhibit smaller deformations than asphalt surfaced pavements.
c -) Block pavements can routinely tolerate much greater recoverable deflections
than those acceptable in asphalt pavemenu.
d) Block pavements tend to stiffen under traffic and may rapidly attain an
equilibrium, lockup condition. once lockup is achieved the pavement has a
greatly reduced sensitivity to changes In either the magnitudes or the numbers of
repetitions of the traffic loads.
e) The performance of a block pavement depends an both the shape and laying
pattern of the blocks. Generally, dentated blocks laid In herringbone pattern are
associated with the best levels of performance.
- - w. arn n* ra inflt]enced b y the thickness a both