Static files load problem Django 1.9

Fri Apr 15 08:13:01 EDT 2016

I have got a problem with static files regarding Django 1.9. These files
are (js,css)  in the standard folder static, inside project folder
directory. I got an error Http 404 that can not be loaded.

Project folder / static / css / several files *.css
                    /static / js / several files   *.js
                     several_apps

i have executed the python manage.py collectstatic

settings.py

STATIC_URL = '/static/'

STATIC_ROOT = os.path.join(BASE_DIR, "static")

STATICFILES_DIRS = (

    os.path.join(BASE_DIR, 'static'),
)

and of course  as INSTALLED_APPS

'django.contrib.staticfiles',

Sorry for my template (at the beginning of my work):

{% load  staticfiles %}

<html>
    <head>
        <link rel="stylesheet"  href="{% static 'css/jquery-ui.css' %}">
        <link rel="stylesheet"  href="{% static 'css/ui.jqgrid.css' %}">
        <script src="{% static 'js/jquery-1.11.0.min.js' %}"
type="text/javascript"> </script>
        <script src="{% static 'js/jquery.jqGrid.min.js' %}"
type="text/javascript"> </script>
        <script src="{% static 'js/grid.locale-el.js' %}"
type="text/javascript"> </script>
        <script src="{% static 'js/category.js' %}" type="text/javascript">
</script>
    </head>
    <body>

        <table id="grid"></table>
        <div id="pager"></div>

    </body>
</html>

but i am afraid the problem lies in urls.py (i do not know what to do)

http://127.0.0.1:8000/static/css/file_name  (in the firebug  network) but i
can not open it directly via server.

urls.py

urlpatterns = [
    url(r'^admin/', admin.site.urls),
    url(r'^hello/','category.views.hello'),
]

Any kind of help would be convenient to me?

Kind Regards
Kostas Asimakopoulos