‘A470 REPORT— 1899. 
forty-five years Parisians walking along the Champs-Elysées dispensed 
with the view of Les Invalides without complaint, proving that it is much 
better to hide entirely a fine view than to spoil it. 
In addition to the foregoing zsthetical considerations, the engineers 
were aware it was the wish of people navigating the Seine that there 
should be no pier in the river bed, the widest possible fairway under the 
bridge, and that consequently the least thickness admissible must be 
selected for the central part of the frame of the bridge. 
General Dimensions of the Bridge.—The bridge consists of a single 
very flat arch, the flooring of which is prolonged over either bank by small 
viaducts, the total length of the bridge between the parapets of the 
banks being 155 metres (509 feet). The abutments of the central arch 
are 109 metres (357 feet) apart. 
The longitudinal axis of the bridge coincides with the axis of the new 
avenue crossing the Seine at an angle of 83° 38’. Its width, 40 metres 
(131 feet), had to harmonise with that of its approaches, the widest bridge 
in Paris up to the present being only 30 metres (98 feet) ; London Bridge is 
54 feet, the Tower Bridge 60 feet, and Brooklyn Bridge 86 feet in width. 
The whole width of the bridge is divided into a central roadway of 
20 metres in width, and into two equal pavements of 10 metres each. 
The gradient of the roadway is 1 in 50, and the highest part of it is 
situated at such a level that an observer standing near the Champs-Elysées. 
in the prolongation of the axis on the right bank will be able to see the 
base of the Hotel des Invalides. 
For reasons which have been already mentioned, the coefficient of rise 
and the thickness of the central cross-section have been reduced to the 
least possible dimensions. The rate of rise to span is 1 to 17. The 
thickness of the central cross section from the bottom flange of the arch 
to the top of the wooden paving on the part of the roadway nearest the 
pavement is no more than 1:02 metres (3 feet 4 inches). 
The conditions obtained for navigation, in consequence of the extreme 
flatness of the arch, though they do not fulfil the wishes of those most 
interested, and are in fact not quite satisfactory at the present time, must. 
be considered as acceptable. The width of the fairway left is no less than 
65 metres (213 feet) in the ordinary state of the river, and 34:4 metres (113 
feet) at high-water time ; the height of free passage being 5°50 metres (18 
feet) above the water level. Moreover the practical inconveniences of the 
present situation may be corrected in the future by the suppression of 
one of the piers of the Invalides Bridge, through the arches of which tugs 
and barges going down the river cannot pass without some difficulty. 
The characteristic features of the new bridge when compared with 
existing bridges may be expressed in these few words : Alexander ITI. 
Bridge is the widest, the flattest, the thinnest skew-arch bridge ever 
constructed in France. By what means have the engineers provided for 
the stability of such a bridge, and how have they erected it without 
interfering with the navigation? These two elements of the problem are 
so intimately connected, that it is not possible to separate them ; both had 
an equal influence on the choice of the type of the arch. 
The bridge consists of fifteen equally distant three-hinged arches, the 
elements of which have been made of cast steel connected by screw-bolts. 
The flooring rests either through the medium of upright pillars, or directly 
on the top of the arches. 
The peculiarities of the triple-hinged arch appeared at once to be 
