MICHIGAN ROADS AND FORESTS 



HIGHWAY BRIDGES AND CULVERTS, fund would make a welcome addition to the stone in most localities prohibits the use of 



(By John J Cox Sturgis Mich ) funds available for road purposes. masonry. We then have left for consideration 



Since the beginning of the present National . In considering the classes or kinds of construe- two kinds of construction, namely, steel and 



t tion, and for convenience in the same, I will concrete, or reinforced concrete. Careful 



movement for good roads, there has been a vast make a distinction between bridges and culverts, study and actual experience with conditions 



amount of discussion and investigation of the I w ;n ca n all spans of six feet and less culverts, has shown that all bridges of fifty feet or 



various elements entering into the work of pro- all above six feet, bridges. My reason for so less should be constructed of concrete or rein- 



viding good roads for countrv districts Good d <> in 8 is, that the construction of greater length forced concrete, as this is the most permanent 



... . .', , , than six feet involve principles of bridge design torm ot construction known to engineers to- 



mdges are a very essential feature of good an( , shouM nQt ^ a mpted by those i nex per- day. The cost of building these permanent 



roads, but little mention has been made of them i ence d and without some knowledge of this sub- structures for such spans is reasonable and 



in the past when good roads were under discus- ject. Some engineers may obpect to this classifi- oftentimes they can be built for the same 



sion This could scarcely have occurred from cation on the grounds of its being misleading, price or but very little more than steel struc- 



. but for the purpose of this paper, the distinction tures with concrete floor, designed for the 



the.r lack of importance ,f importance is to be ; sufficient P sar n e loading. 

 measured by cost as bridges are an item of very . , _, c 



considerable cost both singly and in aggregate. The subject of culvert construction is largely The advantages of concrete over steel 



In the eighty-three counties in the State of one of Iocal conditions and materials. Culverts bridges are as follows: Concrete bridges are 



Michigan in the year 1907. the cost of bridges and are built of wood, vitrified clay pipe, metal, permanent improvements and need neither 



culverts in Branch County alone that same vear masonry and concrete and m the form of boxes, painting nor repairs; they are flood-proof, 



amounted to $13 525. In St. Joseph Countv, ??, arches and sewer shapes. Considering the frost-proof, rust-proof and fire-proof, and 



"',; and this is not an exceptional year but cost and maintenance wood culverts are the have no wooden floors that are periodically 



rather one of minimum expenditure. Let us most expensive culverts built. Following wood out of repair. With the advent of good roads 



look at the year following the year of 1908 closely and almost as high is the corrugated the traffic on our highways grows heavier, 



Branch County raised $- l n 808 for road repair and metal culvert. Aside from being high of cost steel and wooden bridges grow weaker, con- 



42 for highway improvement, making a b th in price and maintenance in many cases crete bridges grow stronger. Concrete 



total of <4 050 as a highway fund Out of this tne y are dangerous. They are made in sizes from bridges are largely built with home labor and 



amount $24.032 was expended on bridges and twelve to sixty inches and their use is not recom- materials. To build a concrete bridge, then 



culverts This is more than 56% of the entire mended. Cast iron comes next m cost and gives the money expended returns directly to the 



highway fund. St. Joseph County raised $10.356 varying results, depending upon the style used, taxpayer, while in steel construction very 



for highway repair and $25.660 for highway im- Cast iron pipe from twelve to forty-eight inches little home labor and materials are used. 

 provement making a total of $36,015 as a "high- makes a very durable culvert. t is not easily Let us take for example a supposed case, 



way fund. $13.75:! was expended on bridges and broken and is put in place without much difficulty. one that is identical to cases occurring in our 



culverts or more than 38% of the entire highway Vitrified clay pipe from 12 to 36 inches makes townships and cities every year. Suppose a 



fund. Neither of these are uncommon expend!- excellent culverts if used in suitable locations town ship wishes to build a bridge of, say, 



tures as most counties spend a large part of their and properly laid. Ihey should not be us I f orty .fo Ot span . This township has a good 



road money for building and maintaining bridges where water will stand in hem as it will : credit with no indebtedness, but is using all 



and culverts. The reason for this is that a large and crack the pipe, nor should they be used near its income for curren t expenses. The town- 



proportion of existing bridges as well as many the surface of the road where the wheels will shjp borrows f rom a barlk $ lj0 oo and buys 



of those now being built are only temporal^ cut them - , N ** comes our masonry culvert, a stee , bridge with wooden fl oor . At inter- 



structures. The fact that our present bridge ex- built of rock. Those built of stratined xk are va)s of five years this bridge is re fl oore d at 



penditure is largely one of maintenance is respon- very satisfactory and especially so up to spans I a cost of abcut ?1(H) for each renewal ^ 



sible for this condition of affairs. 5 feet, but those built in this part of t state intervate of four years the bridge is repainted 



I cannot explain the limited amount of consid- from our Michigan cobble stone only t - at a cost o f $50 for each pa j n ting. Now, at 



erarion given to the subject of bridges unless it porary structures, with varying de S"jees ot - the elld of twenty-five ye ars, in spite of paint- 



is the lack of far-sightedness and of economic faction. The best material to bull ts ol ing and floof renewa i Sj the stee i bridge is 



training along these lines of our communities. is concrete, and in counties, like d bt WQrn Qut and must be rep)aced w j tn a new 



State Highway Engineer of Missouri. Curtis Joseph, where there is an abundant supply ot structure On a 6 per cent basis the interest 



Hill, said in one of his bulletins; "People are in- gravel and often times right ite, ready Qn the $ 1>000 borr owed at the bank has 



appreciative in so far as they are indifferent for use, why should we use anything else. How amounted to $ 60 each year and the ?1 000 



about how their road funds are expended, never cheaply and easily these cone culverts can : stiu remains unpa j d . Qf course a conserva- 



seeming to realize that money is lost if not built is only realized after building t em. lo ; dve township wou i d probably not borrow at 



properly applied to the roads. There is a right- sure the subject needs a 1: le to - the bank> bm jn any case tfae money js wortn 



ful demand for expert supervision of public nected with a small amount ot working knowl- 6 per cfint and the resu , t js the same The 



schools by licensed instructors, but the roads edge of cement and a good allowance >f good township has paid for the first twen ty-five 



which are of next importance and upon which common sense. A better plan still would be > years {he f o ]| ow j ng amounts- 



there is the next largest expenditure, must take standardize these culverts m sizes as rr : as Interest on $ 1>0 00 at $60 per year.. ..$1,500 



care of themselves. Men as a whole are about possible and then limit the number of standard Reflooring every five ars (four times ) 400 



as well fitted to teach school as to make roads, sizes. No culvert should have a width or c R epa i n ting every four years (four times) 250 



To take the expert supervision away from the meter of less than one oot an< larger , A tQta , of $ 2(150> w hi c h amounts to $86 per 



schools and let everybodv try to do the teaching should be expressed m even feet without irac- . and the ?li000 orj inall borrowed still 



would be about as sensible as to let everybody tional parts. After this have a set ot standard unpaid must now be i ncreased to ^QQQ or 



try to make roads. A business would soon be- plans and specihcations drawn and whenever a do withcut a bridge. The township now bor- 



come bankrupt if run in the same manner as the culvert is needed in your township bi id it rows another $ 1>0 oo and builds a new bridge 



road business in some communities." according to these plans and specification By of thg same kind> and fof {he next twem 



t 



ad business in some communities." accoring to tese pans an speciicaion y of thg same kind> and fof {he next 



An authority on road making has said of so doing in a short time you will hnd yourse t fiye & must interest on 2 ,000 amount- 



American ways : "Men are taken from their a long way on the road toward permanent cul- ing tQ $12() a year At the end Q{ fifty yearg 



peculiar occupations in which thev are skilled and verts. the township has paid out $5,800, is $2,000 



transferred to others of which they know noth- Bridges are classified along several different j n debt> and j s w j t hout a bridge. At this 



ing. A good plowman does not think himself H n es, such as according to use, according to ma- rate> at thc end o f seventy-five years the 



competent to forge the coulter of his plow, or to terials used in construction, and according to the township will have paid $ia,950 and be $3,000 



put together the woodwork. He knows it is f ornl o f structure. In fact the classes are so j n deb t an d still have before it the old prob- 



truer economy for him to pay a mechanic for his numerous that it is beyond the scope of this paper i em o f building a bridge. It takes no finan- 



services. But the laws assume him to be a skill- t o take up and discuss each and every class of c j er to see that the building of temporary steel 



ful road-maker a more difficult art than plow- bridge. The bridge we are looking for and the bridges will lead to bankruptcy or higher 



making, and compel him to act as one though his one under discussin, is the economical bridge, taxes. 



clumsiness in repairing his plow would only in- The most economical bridge is that one which in Suppose instead that a permanent concrete 



jure himself, while his road making blunders are the long run will give the best service and cost bridge had been erected, costing one-third 



injurious to the whole community." the least money. The first cost of a bridge is more than the first cost of the steel bridge, 



This same thing is true both of the past and no t a safe criterion upon which to base economy. re q u i r j n g no repairing and no repainting The 



the present in bridge building and to solve this M uc h money is wasted in cheap, flimsy bridges ^^y charge to the township would have been 



problem in bridge economics we must get down which are short lived, unsatisfactory, and con- $ 80 f or interest paid and an indebtedness of 



to the fundamental principals that are involved tinually in need of repairs. The possible life $1,333.33, which would never need to be in- 



in this expenditure and in the remedy. of any bridge is difficult to estimate. Steel creased for that bridge. 



The majority of our bridges are spans of 50 bridges, if properly constructed should last from The customary method of procedure at the 



feet and less, yet the largest portion of the 05 to 40 years ; combination bridges from 12 to ordinary bridge 'letting has a marked tendency 



bridge money is spent in renewing these short 15 years; timber bridges from 10 to 15 years; to lower the standard of highway bridges 



spans. It is evident then that the annual ex- while masonry and reinforced concrete bridges The common method of awarding contracts 



penditures for bridges might eventually be very are permanent structures. has been about as follows: Three or four 



materially reduced by adopting the policy of With the present price of timber and its weeks before the date set for bridge lettings 



renewing these bridges with structures as nearly reduction in quality there are very few occa- the township clerk or other officer advertises 



permanent as may be possible under the circum- s j ons w hen wood or combination construction that bids will be received up to a certain hour 



stances. rom the bridge wou ld be justified, and lack of the proper for building a certain bridge or bridges and 



